This PDF file contains the front matter associated with SPIE Proceedings Volume 10702, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

The Paranal Instrumentation Programme is responsible for planning and delivering the instruments and the associated infrastructures needed to keep the VLT and La Silla Observatories at the forefront of ground-based astronomy. With the commissioning of the Adaptive Optics Facility (AOF), ESPRESSO, and the two VLTI instruments GRAVITY and MATISSE, all second generation VLT instruments have been brought to the observatory and are close to completion. All these instruments and facilities are offered to the users. By keeping the foreseen roadmap (start one new instrument or upgrade every year), the programme is now completing the CRIRES upgrade and the AO systems for the four VLTI Auxiliary Telescopes (NAOMI), integrating the two MOS Instruments MOONS and 4MOST, as well as the AO infrared imager and IFU ERIS. The strategy for la Silla is to dedicate the 3.6m telescope to exo-planet science, by adding the NIRPS spectrograph to the existing HARPS; and to dedicate the NTT to transient science thanks to the new instrument SOXS. Finally, the programme launched a Call for Proposal to study a visible AO imager 7 spectrograph for the Nasmyth focus of the AOF.

We present an overview of the current status of facility instruments at the Large Binocular Telescope (LBT). These include Optical and Near-Infrared instruments: the prime-focus optical Large Binocular Cameras (LBCs); the optical Multi-Object Double Spectrograph (MODS); and the LBT Near-IR Spectroscopic Utility with Camera Instruments (LUCIs). Each side of the telescope contains one of the aforementioned instruments. We detail the recent move to “all binocular all the time” science operations, including the use of multi-mode Adaptive Optics with the LUCIs (diffraction limited over a 30" x 30" field of view or enhanced seeing over a 4' x 4' field of view). Binocular science has three configurations: Duplex mode, with identical configurations on both sides, providing an effective collecting area of 11.9 meters; Fraternal Fraternal Twin or Mixed mode (same instruments with different setups or different instruments on each side, respectively), which is effectively two 8.4 meter telescopes; or interferometry with a 22.6 meter baseline.

Gemini's instrumentation and adaptive optics development efforts continue to grow. We run an active upgrade program for existing instruments, a facility program to bring new instruments to the observatory, and a visitor program that allows teams to bring their own instruments to Gemini for their own and general community science. On the upgrade front, we have finished installing new CCDs into both our GMOS instruments; improved the capabilities of our multi-conjugate adaptive optics system at Gemini South, GeMS; and replaced the lasers in the adaptive optics systems at both our telescopes. GHOST, our new high-resolution optical spectrograph is nearing completion for 2019 delivery and our new 8-band, optical to infrared imager and spectrograph, OCTOCAM, is well into its design phase. Our visiting instruments continue to grow in both number and complexity and we are developing a path to transition selected instruments from our visitor program to become full facility instruments.

Since the start of operations in 1993, the twin 10 meter W. M. Keck Observatory telescopes have continued to maximize their scientific impact and to produce transformative discoveries that keep the observing community on the frontiers of astronomical research. Upgraded capabilities and new instrumentation are provided though collaborative partnerships with Caltech and UC instrument development teams. The observatory adapts and responds to the observers’ evolving needs as defined in the observatory’s strategic plan, periodically refreshed in collaboration with the science community. This paper summarizes the performance of recently commissioned infrastructure projects, technology upgrades, and new additions to the suite of instrumentation at the observatory. We will also provide a status of projects currently in the design or development phase, and since we need to keep our eye on the future, we mention projects in exploratory phases that originate from our strategic plan. Recently commissioned projects include telescope control system upgrades, OSIRIS spectrometer and imager upgrades, and deployments of the Keck Cosmic Web Imager (KCWI), the Near-Infrared Echellette Spectrometer (NIRES), and the Keck I Deployable Tertiary Mirror (KIDM3). Under development are upgrades to the NIRSPEC instrument and adaptive optics (AO) system. Major instrumentation in design phases include the Keck Cosmic Reionization Mapper and the Keck Planet Finder. Future instrumentation studies and proposals underway include a Ground Layer Adaptive Optics system, NIRC2 upgrades, the energy sensitive instrument KRAKENS, an integral field spectrograph LIGER, and a laser tomography AO upgrade. Last, we briefly discuss recovering MOSFIRE and its return to science operations.

The Advanced Instrumentation and Technology Centre (AITC) is a leading technology innovator and instrument builder in Australia for both space and ground based telescopes. The centre is the technology wing of the Research School of Astronomy and Astrophysics at the Australian National University, and has over one hundred years of history in delivering forefront astronomical instrumentation for the national and international community, including NIFS and GSAOI for Gemini Observatory. We present a summary of the ground and space based instrumentation programs under development at the AITC as well as paradigm shifting technology developments underway together with industry and academia.

ERIS is an instrument that will both extend and enhance the fundamental diffraction limited imaging and spectroscopy capability for the VLT. It will replace two instruments that are now being maintained beyond their operational lifetimes, combine their functionality on a single focus, provide a new wavefront sensing module that makes use of the facility Adaptive Optics System, and considerably improve their performance. The instrument will be competitive with respect to JWST in several regimes, and has outstanding potential for studies of the Galactic Center, exoplanets, and high redshift galaxies. ERIS had its final design review in 2017, and is expected to be on sky in 2020. This contribution describes the instrument concept, outlines its expected performance, and highlights where it will most excel.

NIRSPEC is a 1-5 um echelle spectrograph in use on the Keck II Telescope since 1999. The spectrograph is capable of both moderate (R=λ/▵λ~2000) and high (R~25,000) resolution observations and has been a workhorse instrument across many astronomical fields, from planetary science to extragalactic observations. In the latter half of 2018, we will upgrade NIRSPEC to improve the sensitivity and stability of the instrument and increase its lifetime. The major components of the upgrade include replacing the spectrometer and slit-viewing camera detectors with Teledyne H2RG arrays and replacing all transputer-based electronics. We present detailed design, testing, and analysis of the upgraded instrument, including the finalized optomechanical design of the new 1-5 μm slit-viewing camera, detector characterization of the science and Engineering A grade arrays, electronics systems, and updated software design. The optomechanical design of the slit-viewing camera and replacement detector head assembly have both been assembled and cold-tested in our lab. We also show results from the GigE interface to the SAM/ASIC boards to control the H2RG. The upgrade will continue NIRSPEC’s legacy as a powerful near-infrared spectrograph behind one of the world’s most scientifically productive telescopes.

The LUCI instruments are a pair of NIR imagers and multi-object spectrographs located at the front bent Gregorian foci of the Large Binocular Telescope (LBT). One of their special features is their diffraction-limited imaging and long-slit spectroscopic capability in combination with the LBT adaptive secondary mirrors. This allows to achieve a spatial resolution down to 60mas and a spectral resolution of up to 25000. Switching from seeing-limited to diffraction-limited observations changes several operational aspects due to features such as the non-common path aberration or the flexure of the instruments. They all require novel techniques to optimize the image quality and to maximize the scientific return. Non-common path aberration can be corrected via look-up tables. For active flexure compensation the night-sky emission is used. The commissioning of the instruments in diffraction-limited mode on sky is largely finished and the instruments have been handed over to the LBT in April 2018.

The Arizona Lenslets for Exoplanet Spectroscopy (ALES) is the world’s first AO-fed thermal infrared integral field spectrograph, mounted inside the Large Binocular Telescope Interferometer (LBTI) on the LBT. An initial mode of ALES allows 3-4 μm spectra at R 20 with 0.026” spaxels over a 1”x1” field-of-view. We are in the process of upgrading ALES with additional wavelength ranges, spectral resolutions, and plate scales allowing a broad suite of science that takes advantage of ALES’s unique ability to work at wavelengths >2 microns, and at the diffraction limit of the LBT’s full 23.8 meter aperture.

By adding a dedicated coronagraph, ESO in collaboration with the Breakthrough Initiatives, modifies the Very Large Telescope mid-IR imager (VISIR) to further boost the high dynamic range imaging capability this instru- ment has. After the VISIR upgrade in 2012, where coronagraphic masks were first added to VISIR, it became evident that coronagraphy at a ground-based 8m-class telescope critically needs adaptive optics, even at wavelengths as long as 10μm. For VISIR, a work-horse observatory facility instrument in normal operations, this is ”easiest” achieved by bringing VISIR as a visiting instrument to the ESO-VLT-UT4 having an adaptive M2. This “visit” enables a meaningful search for Earth-like planets in the habitable zone around both α-Cen1,2. Meaningful here means, achieving a contrast of ≈ 10^-6 within ≈ 0.8arcsec from the star while maintaining basically the normal sensitivity of VISIR. This should allow to detect a planet twice the diameter of Earth. Key components will be a diffractive coronagraphic mask, the annular groove phase mask (AGPM), optimized for the most sensitive spectral band-pass in the N-band, complemented by a sophisticated apodizer at the level of the Lyot stop. For VISIR noise filtering based on fast chopping is required. A novel internal chopper system will be integrated into the cryostat. This chopper is based on the standard technique from early radio astronomy, conceived by the microwave pioneer Robert Dicke in 1946, which was instrumental for the discovery of the 3K radio background.

The CRIRES upgrade project (CRIRES+) will improve the performance and observing efficiency of the successful adaptive optics (AO) assisted CRIRES instrument. CRIRES was in operation from 2006 to 2014 at the 8m UT1 (Unit Telescope) of the Very Large Telescope (VLT, Cerro Paranal, Chile) observatory accessing a parameter space (wavelength range and spectral resolution) largely uncharted back then. CRIRES+ will be commissioned in summer 2018 at UT3 of the VLT. It will provide a spectral resolution of R=50.000 or 100.000 in an accessible wavelength range of 0.95 – 5.3 μm (YJHKLM bands). For each band there is a separate, performance optimized reflection grating as the cross dispersing element. The slit length of 10 arcsec will provide, in combination with the new focal plane array of three HAWAII 2RG detectors, cross-dispersed (7 – 9 orders simultaneous) echelle spectra. In total, the observing efficiency will be improved by a factor of 10 comparing CRIRES+ and CRIRES. Furthermore, the upgraded instrument will be equipped with a number of novel wavelength calibration units, including a gas absorption cell optimized for use in K band and an etalon system. A spectro-polarimetric unit will allow the recording of circular and linear polarized spectra. The new metrology system will ensure a very high system stability and repeatability. Last but not least the upgrade will be supported by dedicated data reduction software allowing the community to take full advantage of the new capabilities. The full system is being integrated at ESO and system testing has commenced. Acceptance of the instrument in Europe (PAE) is scheduled for the second quarter of 2018. Commissioning at the VLT observatory will start mid 2018. This article gives an overview of the final configuration of the instrument. The instrument will be available to the astronomic community from Spring 2019 with a call for proposals in October 2018.

SOXS (Son Of X-Shooter) will be a spectrograph for the ESO NTT telescope capable to cover the optical and NIR bands, based on the heritage of the X-Shooter at the ESO-VLT. SOXS will be built and run by an international consortium, carrying out rapid and longer term Target of Opportunity requests on a variety of astronomical objects. SOXS will observe all kind of transient and variable sources from different surveys. These will be a mixture of fast alerts (e.g. gamma-ray bursts, gravitational waves, neutrino events), mid-term alerts (e.g. supernovae, X-ray transients), fixed time events (e.g. close-by passage of minor bodies). While the focus is on transients and variables, still there is a wide range of other astrophysical targets and science topics that will benefit from SOXS. The design foresees a spectrograph with a Resolution-Slit product ≈ 4500, capable of simultaneously observing over the entire band the complete spectral range from the U- to the H-band. The limiting magnitude of R~20 (1 hr at S/N~10) is suited to study transients identified from on-going imaging surveys. Light imaging capabilities in the optical band (grizy) are also envisaged to allow for multi-band photometry of the faintest transients. This paper outlines the status of the project, now in Final Design Phase.

The OCTOCAM instrument concept was built on the principles of efficiency and simultaneity. The aim was not only optical throughput and excellent detector response, but also broad wavelength coverage, temporal resolution and a very good duty cycle to make the best possible use of every photon collected by a telescope. This instrument would be optimized for the study of transient astronomical sources. This lead to a multi-channel instrument with the capability of doing imaging and spectroscopy, which is currently being developed for the 8.1m Gemini South telescope. In the Gemini implementation, OCTOCAM will perform imaging of a 3'x3' field of view in 8 simultaneous channels (g, r, i, z, Y, J, H, Ks) or long slit (3') spectroscopy covering the range between 3700 and 23500 Angstrom at a resolution of ~4000. In this talk I will present the OCTOCAM instrument concept, the origin and development of the idea and the path to becoming a reality at an 8 m class telescope. I will cover the technical, management and personal lessons learned throughout a decade long path from the experience of the principal investigator of the project, which I was, from the beginning and until the end of 2017. Finally I will comment on the possible reinterpretations of OCTOCAM on smaller and larger telescopes.

Microwave Kinetic Inductance Detectors, or MKIDS, have the ability to simultaneous resolve the wavelength of individual photons and time tag photons with microsecond precision. This opens up a number of exciting new possibilities and efficiency gains for optical/IR astronomy. In this paper we describe a plan to take the MKID technology, which we have demonstrated on the Palomar, Lick, and Subaru Telescopes, out of the realm of private instruments usable only by experts. Our goal is to incorporate MKIDs into a facility-class instrument at the Keck 1 Telescope that can be used by a large part of the astronomical community. This new instrument, the Keck Radiometer Array using KID ENergy Sensors (KRAKENS), will be a 30 kpix integral field spectrograph (IFS) with a 42.5” x 45” field of view, extraordinarily wide wavelength coverage from 380-1350 nm, and a spectral resolution R=λ/▵λ > 20 at 400 nm. Future add on modules could enable polarimetry and higher spectral resolution. KRAKENS will be built using the same style MKID arrays, cryostat, and similar readout electronics to those used in the successful 10 kpix DARKNESS instrument at Palomar and 20 kpix MEC instrument at Subaru, significantly reducing the technical risk.

We present the current status of the SCORPIO project, the facility instrument for Gemini South designed to perform follow up studies of transients in the LSST era while carrying out with unique efficiency a great variety of astrophysical programs. SCORPIO operates in the wavelength range 385-2350 nanometers, observing simultaneously in the grizYJHK bands. It can be used both in imaging (seeing limited) and spectroscopic (long-slit) mode, and thanks to the use of frame-transfer CCDs it can monitor variable sources with milli-second time-resolution. The project has recently passed PDR and is on schedule to be commissioned at the time of the LSST first light.

The Tomo-e Gozen is a wide-field high-speed camera for the Kiso 1.0-m Schmidt telescope, with a field-of-view of 20.7-deg² covered by 84 chips of 2k x 1k CMOS image sensors with 19-μm pixels. It is capable to take consecutive images at 2-fps in full-frame read with an absolute time accuracy of 0.2 millisecond. The sensors are operated without mechanical coolers owing to a low dark current at room temperature. A low read noise of 2-e^- achieves higher sensitivity than that with a CCD sensor in short exposures. Big data of 30-TBytes per night produced in the 2-fps observations is processed in real-time to quickly detect transient events and issue alerts for follow-ups.

The Evryscope is a new type of array telescope which monitors the entire accessible sky in each exposure. One Evryscope has covered the Southern hemisphere from Chile since 2015, and we will soon deploy another Evryscope to cover the North from Mount Laguna Observatory in California. Each telescope, with 692 MPix covering an 8000-square-degree field of view, builds many-year-length, high-cadence light curves for every accessible object brighter than ~16th magnitude. An overlapping 4000-square-degree region between each system will give simultaneous multicolor observations with a 8,500km baseline. Every night, we add more than a billion object detections to our databases, enabling the detection of exoplanet transits, microlensing events, nearby extragalactic transients, gravitational wave electromagnetic counterparts, and a wide range of other short timescale events. The Evryscopes are designed to complement surveys such as TESS, providing multi-color context, longer-term observations and higher cadence across the sky. Although the Evryscope telescopes are small, they integrate for more than 6 hours on each part of the sky each night, enabling the system to form high-cadence counterparts to surveys such as LSST. All data, over 600Gb per night, is recorded for realtime analysis. Co-adding achieves depths of g>17 each hour across the entire accessible sky, and our on-site pipelines add all object detections to our databases in realtime. I will discuss the system design, including building the telescopes for fully-robotic operation, actuating our lens-camera interface at few-micron precisions to optimize our image quality, and the big-data analysis required to explore the petabyte-scale dataset we are collecting over the next few years. I will also present the first results from the Southern Evryscope.

HiPERCAM is a quintuple-beam imager that saw first light on the 4.2 m William Herschel Telescope (WHT) in October 2017 and on the 10.4 m Gran Telescopio Canarias (GTC) in February 2018. The instrument uses re- imaging optics and 4 dichroic beamsplitters to record ugriz (300–1000 nm) images simultaneously on its five CCD cameras. The detectors in HiPERCAM are frame-transfer devices cooled thermo-electrically to 90°C, thereby allowing both long-exposure, deep imaging of faint targets, as well as high-speed (over 1000 windowed frames per second) imaging of rapidly varying targets. In this paper, we report on the as-built design of HiPERCAM, its first-light performance on the GTC, and some of the planned future enhancements.

Zwicky Transient Facility is an integrated, multi-band astronomical survey system optimized for sensitivity, observing cadence, and efficiency. The key subsystem consists of a 600 megapixel CCD focal plane mounted in a flat-fielding vacuum cryostat, located at the prime focus of the 1.2-meter Samuel Oschin Telescope at Palomar Observatory. Supporting subsystems include a new 2.4-meter optical shutter assembly, a 1.35-meter diameter aspheric corrector plate, a cryostat stabilizing hexapod, a commercial robotic arm-based exchanger, three 440 millimeter width filters, four guide/focus CCDs, and dedicated optics compensating individual field curvature over each of sixteen 6k x 6k science CCDs.To optimize ZTF efficiency, all telescope and dome drives were upgraded for higher speed and acceleration, fast readout electronics were implemented, and a sophisticated robotic control system has been implemented. We present for the first time on-sky results from the recently completed ZTF including its realized optical image quality, CCD noise, and observing efficiency performance and discuss engineering challenges that have been overcome. Early scientific results from the ZTF survey are also included.

Time has come to implement a new way to study the stellar physics from the ground with long-term uninterrupted time series, multi-color photometry, flexibility during observing runs and all for less money. PAIX, Photometer AntarctIca eXtinction, gives new insight to cope with unresolved stellar enigma and stellar oscillation challenges and bears witness, for the first time, to a new technology of the polar instrumental robotization under extreme human and weather conditions in the heart of Antarctica. In fact, the stellar pulsation plays a crucial role in understanding the Universe, however progress is limited by the data accuracy needed to detect numerous modes of oscillations with small amplitudes and by the discontinuous nature of typical ground-based data strings which often introduce ambiguities in the determination of oscillation frequencies. The recent space missions enable to overcome both difficulties, However, the outcome of the space missions shows large gaps in terms of flexibility during the observing runs, the choice of targets, the repair of failures and the inexorable high costs. We present here the new technology from Antarctica, in particular from South Polar Site Dome C that benefits from great image quality and 150 days high time coverage, where the seeing reaches a median value of 1 arcsec during the polar night. We briefly describe the instrumental performances of PAIX, its low-cost commercial components, robotic telescope, multi-band photometer and automatic control, working under harsh weather conditions, even when the temperature reach values as low as -80°C. The polar mission PAIX challenges the space missions and even has more advantages than CoRoT and KEPLER in observing in UBVRI bands and then collecting multicolor light curves simultaneously of several targets. We discuss here the first outcomes of stellar physics from the heart of Antarctica during 10 polar nights and PAIX new results and perspectives on the pulsating stars from Antarctica, especially the connection between the stellar pulsation enigma and the Universe mysteries. Finally, we highlight the impact of PAIX -the robotic Antarctica photometer- on the Astronomy development.

In this paper, we present the preliminary optical system design of AST3-NIR camera, a wide-field infrared imager for 50cm Antarctic surveying telescope (AST3-3) to be deployed to Dome A, the Antarctic plateau. It is a joint project in which China is responsible for telescope hardware and control, logistics and deployment. Australia is responsible for instrument hardware design and control, and power generation. The camera uses two mosaic Leonardo detectors with 1280 x 1032 pixels each. The instrument is designed with a field of view(FOV) of 28.10 X 46.10 at the pixel scale of 1.35” per 15µm pixel. It is optimized for K dark band (2.26μm to 2.49 μm). The main challenges of this design are to produce a well-defined internal pupil stop located within cryogenic condition which reduces the thermal background and the correction of off-axis aberrations due to the large available field. Since the operating temperature of the camera could vary from -35°C to -90°C, the refocusing mechanism needs to be designed within the camera. The optical performance of the system will be demonstrated. We show the opto-mechanical error budget and compensation strategy that allows the built design to meet the optical performance.

The problem of atmospheric emission from OH molecules is a long standing problem for near-infrared astronomy. PRAXIS is a unique spectrograph which is fed by fibres that remove the OH background and is optimised specifically to benefit from OH-Suppression. The OH suppression is achieved with fibre Bragg gratings, which were tested successfully on the GNOSIS instrument. PRAXIS uses the same fibre Bragg gratings as GNOSIS in its first implementation, and will exploit new, cheaper and more efficient, multicore fibre Bragg gratings in the second implementation. The OH lines are suppressed by a factor of ∼ 1000, and the expected increase in the signal-to-noise in the interline regions compared to GNOSIS is a factor of ∼ 9 with the GNOSIS gratings and a factor of ∼ 17 with the new gratings. PRAXIS will enable the full exploitation of OH suppression for the first time, which was not achieved by GNOSIS (a retrofit to an existing instrument that was not OH-Suppression optimised) due to high thermal emission, low spectrograph transmission and detector noise. PRAXIS has extremely low thermal emission, through the cooling of all significantly emitting parts, including the fore-optics, the fibre Bragg gratings, a long length of fibre, and the fibre slit, and an optical design that minimises leaks of thermal emission from outside the spectrograph. PRAXIS has low detector noise through the use of a Hawaii-2RG detector, and a high throughput through a efficient VPH based spectrograph. PRAXIS will determine the absolute level of the interline continuum and enable observations of individual objects via an IFU. In this paper we give a status update and report on acceptance tests.

The Immersion GRating INfrared Spectrometer (IGRINS) was designed for high-throughput with the expectation of being a visitor instrument at progressively larger observing facilities. IGRINS achieves R∼45000 and > 20,000 resolution elements spanning the H and K bands (1.45-2.5μm) by employing a silicon immersion grating as the primary disperser and volume-phase holographic gratings as cross-dispersers. After commissioning on the 2.7 meter Harlan J. Smith Telescope at McDonald Observatory, the instrument had more than 350 scheduled nights in the first two years. With a fixed format echellogram and no cryogenic mechanisms, spectra produced by IGRINS at different facilities have nearly identical formats. The first host facility for IGRINS was Lowell Observatory’s 4.3-meter Discovery Channel Telescope (DCT). For the DCT a three-element fore-optic assembly was designed to be mounted in front of the cryostat window and convert the f/6.1 telescope beam to the f/8.8 beam required by the default IGRINS input optics. The larger collecting area and more reliable pointing and tracking of the DCT improved the faint limit of IGRINS, relative to the McDonald 2.7-meter, by ∼1 magnitude. The Gemini South 8.1-meter telescope was the second facility for IGRINS to visit. The focal ratio for Gemini is f/16, which required a swap of the four-element input optics assembly inside the IGRINS cryostat. At Gemini, observers have access to many southern-sky targets and an additional gain of ∼1.5 magnitudes compared to IGRINS at the DCT. Additional adjustments to IGRINS include instrument mounts for each facility, a glycol cooled electronics rack, and software modifications. Here we present instrument modifications, report on the success and challenges of being a visitor instrument, and highlight the science output of the instrument after four years and 699 nights on sky. The successful design and adaptation of IGRINS for various facilities make it a reliable forerunner for GMTNIRS, which we now anticipate commissioning on one of the 6.5 meter Magellan telescopes prior to the completion of the Giant Magellan Telescope.

Balloon-borne astronomy is a unique tool that allows for a level of image stability and significantly reduced atmospheric interference without the often prohibitive cost and long development time-scale that are characteristic of space-borne facility-class instruments. The Super-pressure Balloon-borne Imaging Telescope (SuperBIT) is a wide-field imager designed to provide 0.02" image stability over a 0.5 degree field-of-view for deep exposures within the visible-to-near-UV (300-900 um). As such, SuperBIT is a suitable platform for a wide range of balloon-borne observations, including solar and extrasolar planetary spectroscopy as well as resolved stellar populations and distant galaxies. We report on the overall payload design and instrumentation methodologies for SuperBIT as well as telescope and image stability results from two test flights. Prospects for the SuperBIT project are outlined with an emphasis on the development of a fully operational, three-month science flight from New Zealand in 2020.

Since its first light at the VLT in 2012, the Annular Groove Phase Mask (AGPM) has been used to implement vortex coronagraphy into AO-assisted infrared cameras at two additional world-leading observatories: the Keck Observatory and the LBT. In this paper, we review the status of these endeavors, and briefly highlight the main scientific results obtained so far. We explore the performance of the AGPM vortex coronagraph as a function of instrumental constraints, and identify the main limitations to the sensitivity to faint, off-axis companions in high-contrast imaging. These limitations include the AGPM itself, non-common path aberrations, as well as the data processing pipeline; we briefly describe our on-going efforts to further improve these various aspects. Based on the lessons learned from the first five years of on-sky exploitation of the AGPM, we are now preparing its implementation in a new generation of high-contrast imaging instruments. We detail the specificities of these instruments, and how they will enable the full potential of vortex coronagraphy to be unleashed in the future. In particular, we explain how the AGPM will be used to hunt for planets in the habitable zone of alpha Centauri A and B with a refurbished, AO-assisted version of the VISIR mid-infrared camera at the VLT (aka the NEAR project), and how this project paves the way towards mid-infrared coronagraphy on the ELT with the METIS instrument. We also discuss future LM-band applications of the AGPM with VLT/ERIS, ELT/METIS, and with a proposed upgrade of Keck/NIRC2, as well as future applications at shorter wavelengths, such as a possible upgrade of VLT/SPHERE with a K-band AGPM.

This paper reports on the installation and initial commissioning of LINC-NIRVANA (LN), an innovative high resolution, near-infrared imager for the Large Binocular Telescope (LBT). We present the delicate and difficult installation procedure, the culmination of a re-integration campaign that was in full swing at the last SPIE meeting. We also provide an update on the ongoing commissioning campaigns, including our recent achievement of First Light. Finally, we discuss lessons learned from the shipment and installation of a large complex instrument.

Direct Imaging of exoplanets is one of the most technically difficult techniques used to study exoplanets, but holds immense promise for not just detecting but characterizing planets around the nearest stars. Ambitious instruments at the world’s largest telescopes have been built to carry out this science: the Gemini Planet Imager (GPI), SPHERE at VLT, SCExAO at Subaru, and the P1640 and Stellar Double Coronagraph (SDC) at Palomar. These instruments share a common archetype consisting of an extreme AO system feeding a coronagraph for on-axis stellar light rejection followed by a focal plane Integral Field Spectrograph (IFS). They are currently limited by uncontrolled scattered and diffracted light which produces a coherent speckle halo in the image plane. A number of differential imaging schemes exist to mitigate these issues resulting in star-planet contrast ratios as deep as ~10^-6 at low angular separations. Surpassing this contrast limit requires high speed active speckle nullification from a focal plane wavefront sensor (FPWS) and new processing techniques. MEC, the Microwave Kinetic Inductance Detector (MKID) Exoplanet Camera, is a J-band IFS module behind Subaru Telescope’s SCExAO system. MEC is capable of producing an image cube several thousand times a second without the read noise that dominates conventional high speed IFUs. This enables it to integrate with SCExAO as an extremely fast FPWS while eliminating non-common path aberrations by doubling as a science camera. Key science objectives can be further explored if longer wavelengths (H and K band) are simultaneously sent to CHARIS for high resolution spectroscopy. MEC, to be commissioned at Subaru in early 2018, is the second MKID IFS for high contrast imaging following DARKNESS’ debut at Palomar in July 2016. MEC will follow up on young planets and debris disks discovered in the SEEDS survey or by Project 1640 as well as discover self-luminous massive planets. The increased sensitivity, combined with the advanced coronagraphs in SCExAO which have inner working angles (IWAs) as small as 0.03” at 1.2 μm, allows young Jupiter-sized objects to be imaged as close as 4 AU from their host star. If the wavefront control enabled by MEC is fully realized, it may begin to probe the reflected light of giant planets around some nearby stars, opening a new parameter space for direct imaging targeting older stars. While direct imaging of reflected light exoplanets is the most challenging of the scientific goals, it is a promising long-term path towards characterization of habitable planets around nearby stars using Extremely Large Telescopes (ELTs). With diameters of about 30-m, an ELT can resolve the habitable zones of nearby M-type stars, for which an Earth-sized planet would be at ~10^-7 contrast at 1 μm. This will complement future space-based high contrast optical imaging targeting the wider habitable zones of sun-like stars for ~10^-10 contrast earth analogs. We will present lessons learned from the first few months of MEC’s operation including initial lab and on-sky (weather permitting) results. We already have preliminary data from Palomar testing a new statistical speckle discrimination post-processing technique using the photon arrival time measured with MKIDs. Residual stellar light in the form of a speckle masquerading as a planetary companion is pulled from a modified Rician distribution and can be statistically discerned from a true off-axis Poisson point source. Additionally, the progress of active focal plane wavefront control will be briefly discussed.

The design and construction of CARMENES has been presented at previous SPIE conferences. It is a next-generation radial-velocity instrument at the 3.5m telescope of the Calar Alto Observatory, which was built by a consortium of eleven Spanish and German institutions. CARMENES consists of two separate échelle spectrographs covering the wavelength range from 0.52 to 1.71μm at a spec-tral resolution of R < 80,000, fed by fibers from the Cassegrain focus of the telescope. CARMENES saw “First Light” on Nov 9, 2015. During the commissioning and initial operation phases, we established basic performance data such as throughput and spectral resolution. We found that our hollow-cathode lamps are suitable for precise wavelength calibration, but their spectra contain a number of lines of neon or argon that are so bright that the lamps cannot be used in simultaneous exposures with stars. We have therefore adopted a calibration procedure that uses simultaneous star / Fabry Pérot etalon exposures in combination with a cross-calibration between the etalons and hollow-cathode lamps during daytime. With this strategy it has been possible to achieve 1-2 m/s precision in the visible and 5-10 m/s precision in the near-IR; further improvements are expected from ongoing work on temperature control, calibration procedures and data reduction. Comparing the RV precision achieved in different wavelength bands, we find a “sweet spot” between 0.7 and 0.8μm, where deep TiO bands provide rich RV information in mid-M dwarfs. This is in contrast to our pre-survey models, which predicted comparatively better performance in the near-IR around 1μm, and explains in part why our near-IR RVs do not reach the same precision level as those taken with the visible spectrograph. We are now conducting a large survey of 340 nearby M dwarfs (with an average distance of only 12pc), with the goal of finding terrestrial planets in their habitable zones. We have detected the signatures of several previously known or suspected planets and also discovered several new planets. We find that the radial velocity periodograms of many M dwarfs show several significant peaks. The development of robust methods to distinguish planet signatures from activity-induced radial velocity jitter is therefore among our priorities. Due to its large wavelength coverage, the CARMENES survey is generating a unique data set for studies of M star atmospheres, rotation, and activity. The spectra cover important diagnostic lines for activity (H alpha, Na I D1 and D2, and the Ca II infrared triplet), as well as FeH lines, from which the magnetic field can be inferred. Correlating the time series of these features with each other, and with wavelength-dependent radial velocities, provides excellent handles for the discrimination between planetary companions and stellar radial velocity jitter. These data are also generating new insight into the physical properties of M dwarf atmospheres, and the impact of activity and flares on the habitability of M star planets.

ESPRESSO is the next generation Euro- pean exoplanet hunter, combining the ef ciency of a modern echelle spectro- graph with extreme radial velocity and spectroscopic precision. ESPRESSO will be installed in the Combined Coudé Laboratory of the VLT and linked to the four Unit Telescopes (UT) through optical coudé trains, operated either with a single UT or with up to four UTs for 1.5 magnitude gain. The instrumental radial velocity precision will reach the 10 cm s–1 level and ESPRESSO will achieve a gain of two magnitudes with respect to its predecessor HARPS. This is the first VLT instrument using the incoherent combination of light from four telescopes and, together with the extreme precision requirements, calls for many innovative design solutions while ensuring the technical heritage of HARPS. The main scientific drivers for ESPRESSO are the search and characterisation of rocky exoplanets in the habitable zone of quiet, nearby G to M dwarf stars and the analysis of the variability of fundamental physical constants. As an ultra­stable high­resolution spectrograph however, ESPRESSO will allow new frontiers to be explored in most domains of astrophys­ics. The instrument has been installed at the Paranal Observatory in 2017 and will begin official operations by October 2018. High ­resolution spectroscopy has always been at the heart of astrophysics. It pro­vides the data that bring physical insight into the behaviour of stars, galaxies, interstellar and intergalactic media. Corre­spondingly, high-­resolution spectro­graphs have always been in high demand at major observatories, see, e.g., UVES at the VLT or HIRES at the Keck Tele­scope. As telescope apertures become larger, the capabilities of high-­resolution spectrographs extend to fainter and fainter objects. Besides this increase in photon-­collecting power, another aspect has emerged in recent years: the power of high-precision spectroscopy. In many applications there is the need for highly repeatable observations over long time­ scales where instrumental effects must be completely removed, or at least mini­mised. For instance, this is the case for radial velocity (RV) measurements, or, more generally, for the determination of the positions and shapes of spectral lines. In this respect, the HARPS spectrograph at the ESO 3.6-metre telescope (Mayor et al., 2003) has been a pioneering instru­ment. It has been widely recognised in the European astronomical community that a similar instrument on the VLT would be necessary. The need for a ground­based follow­up facility capable of high RV precision was stressed in the ESO–ESA working group report on extrasolar planets (Perryman et al., 2005). The research area “terrestrial planets in the habitable zone” is one of the main scientific topics for the next few decades in astronomy, and one of the main science drivers for the new gen­eration of extremely large telescopes (ELTs). For instance, the ESO–ESA working group report calls for “high-­precision radial-velocity instrumentation for the follow-­up of astro­metric and transit detections, to ensure the detection of a planet by a second in­dependent method, and to determine its true mass. For Jupiter­-mass planets, existing instrumentation may be techni­cally adequate, but observing time inade­quate; for Earth­-mass candidates, special-purpose instrumentation (like HARPS) on a large telescope would be required.” (Perryman et al., 2005, p. 63). The same concept is reiterated in the first recom­mendation: “Support experiments to im­ prove RV mass detection limits, e.g., based on experience from HARPS, down to those imposed by stellar surface phe­nomena” (Perryman et al., 2005, p. 72). Do the fundamental constants vary? This is one of the six big open questions in cosmology as listed in the ESA–ESO working group report for fundamental cosmology (Peacock et al., 2006). In the executive summary, the document states: “Quasar spectroscopy also offers the possibility of better constraints on any time variation of dimensionless atomic parameters such as the fine-structure constant α and the proton-­to-­electron mass ratio. Presently there exist controversial claims of evidence for variations in α, which potentially relate to the dynam­ics of dark energy. It is essential to vali­date these claims with a wider range of targets and atomic tracers.” This goal can only be reached with improved spec­troscopic capabilities. In this context the ESO Scientific Technical Committee (STC) recommended, at its 67th meeting in October 2007, the development of additional second gener­ation VLT instruments, and its detailed proposal was endorsed by the ESO Council at its 111th meeting in December 2007. Among the recommended instru­ments, a high-­resolution, ultra-­stable spectrograph for the VLT combined coudé focus arose as a cornerstone to com­plete the current second generation VLT instrument suite. In March 2007, following these recommendations, ESO issued a call for proposals, open to Member State institutes or consortia, to carry out the Phase A study for such an instrument. The submitted proposal was accepted by ESO and the ESPRESSO consortium was selected to carry out the project for the construction of this spectrograph. The main scientfiic drivers for this project were de ned by ESO as follows: 1. Measure high­-precision RV to search for rocky planets. 2. Measure the variation of physical con­stants. 3. Analyse the chemical composition of stars in nearby galaxies. The official project kick-off was held in February 2011. The design phase lasted about 2.5 years and ended with the final design review (FDR) in May 2013. The procurement of components and manu­facturing of subsystems lasted longer than planned due to manufacturing difficulties. Early 2015 the first subsystems were ready for integration in Europe, but Provisional Acceptance Europe of the instrument (the end integration and Verification) could only be held in June 2017. The transfer of the instrument to Paranal, installation took place in August-November 2017. The commission time cover the southern summer 2017-2018. Acceptance Paranal is planned to take place mid-2018. ESPRESSO is a fibre-fed, cross-dispersed, high-resolution, echelle spectrograph. The telescope light is fed to the instrument via a so-called ‘Coudé-Train’ optical system and within optical fibres. ESPRESSO is located in the Combined-Coudé Laboratory (incoherent focus) where a front-end unit can combine the light from up to 4 Unit Telescopes (UT) of the VLT. The target and sky light enter the instrument simultaneously through two separate fibres, which form together the ‘slit’ of the spectrograph. Several optical ‘tricks’ have been used to obtain high spectral resolution and efficiency despite the large size of the telescope and the 1 arcscec sky aperture of the instrument. At the spectrograph entrance the Anamorphic Pupil Slicing Unit (APSU) shapes the beam in order to compress it in cross-dispersion and splits in two smaller beams, while superimposing them on the echelle grating to minimize its size. The rectangular white pupil is then re-imaged and compressed. Given the wide spectral range, a dichroic beam splitter separates the beam in a blue and a red arm, which in turn allows to optimizing each arm for image quality and optical efficiency. The cross-disperser has the function of separating the dispersed spectrum in all its spectral orders. In addition, an anamorphism is re-introduced to make the pupil square and to compress the order height such that the inter-order space and the SNR per pixel are both maximized. Both functions are accomplished using Volume Phase Holographic Gratings (VPHGs) mounted on prisms. Finally, two optimised camera lens systems image the full spectrum from 380 nm to 780 nm on two large 92 mm x 92 mm CCDs with 10-um pixels.

Veloce is an ultra-stable fibre-fed R4 echelle spectrograph for the 3.9 m Anglo-Australian Telescope. The first channel to be commissioned, Veloce ‘Rosso’, utilises multiple low-cost design innovations to obtain Doppler velocities for sun-like and M-dwarf stars at <1 ms ^-1 precision. The spectrograph has an asymmetric white-pupil format with a 100-mm beam diameter, delivering R>75,000 spectra over a 580-930 nm range for the Rosso channel. Simultaneous calibration is provided by a single-mode pulsed laser frequency comb in tandem with a traditional arc lamp. A bundle of 19 object fibres ensures full sampling of stellar targets from the AAT site. Veloce is housed in dual environmental enclosures that maintain positive air pressure at a stability of ±0.3 mbar, with a thermal stability of ±0.01 K on the optical bench. We present a technical overview and early performance data from Australia's next major spectroscopic machine.

GIARPS (GIAno and haRPS) is a project devoted to have on the same focal station of the Telescopio Nazionale Galileo (TNG) both high resolution spectrographs, HARPS–N (VIS) and GIANO–B (NIR), working simultaneously. This could be considered the first and unique worldwide instrument providing cross-dispersed echelle spectroscopy at a resolution of 50,000 in the NIR range and 115,000 in the VIS and over in a wide spectral range (0.383−2.45 μm) in a single exposure. The science case is very broad, given the versatility of such an instrument and its large wavelength range. A number of outstanding science cases encompassing mainly extra-solar planet science starting from rocky planets search and hot Jupiters to atmosphere characterization can be considered. Furthermore both instruments can measure high precision radial velocities by means the simultaneous thorium technique (HARPS–N) and absorbing cell technique (GIANO–B) in a single exposure. Other science cases are also possible. GIARPS, as a brand new observing mode of the TNG started after the moving of GIANO–A (fiber fed spectrograph) from Nasmyth–A to Nasmyth–B where it was re–born as GIANO–B (no more fiber feed spectrograph). The official Commissioning finished on March 2017 and then it was offered to the community. Despite the work is not finished yet. In this paper we describe the preliminary scientific results obtained with GIANO–B and GIARPS observing mode with data taken during commissioning and first open time observations.

NIRPS (Near Infra Red Planet Searcher) is a new ultra-stable infrared ( YJH) fiber-fed spectrograph that will be installed on ESO’s 3.6-m telescope in La Silla, Chile. Aiming at achieving a precision of 1 m/s, NIRPS is designed to find rocky planets orbiting M dwarfs, and will operate together with HARPS (High Accuracy Radial velocity Planet Searcher). In this paper we describe NIRPS science cases, present its main technical characteristics and its development status.

The Infrared Doppler (IRD) instrument is a fiber-fed high-resolution NIR spectrometer for the Subaru telescope covering the Y,J,H-bands simultaneously with a maximum spectral resolution of 70,000. The main purpose of IRD is a search for Earth-mass planets around nearby M-dwarfs by precise radial velocity measurements, as well as a spectroscopic characterization of exoplanet atmospheres. We report the current status of the instrument, which is undergoing commissioning at the Subaru Telescope, and the first light observation successfully done in August 2017. The general description of the instrument will be given including spectrometer optics, fiber injection system, cryogenic system, scrambler, and laser frequency comb. A large strategic survey mainly focused on late-type M-dwarfs is planned to start from 2019.

PEPSI is the new fiber-fed and stabilized “Potsdam Echelle Polarimetric and Spectroscopic Instrument” for the Large Binocular Telescope (LBT). It covers the entire optical wavelength range from 384 to 913 nm in three exposures at resolutions of either R=λ/▵λ=50,000, 130,000 or 250,000. The R=130,000 mode can also be used with two dual-beam Stokes IQUV polarimeters. The 50,000-mode with its 12-pix sampling per resolution element is our “bad seeing” or “faint-object” mode. A robotic solar-disk-integration (SDI) telescope feeds solar light to PEPSI during day time and a 450-m fiber feed from the 1.8m VATT can be used when the LBT is busy otherwise. CCD characterization and a removal procedure for the spatial fixed-pattern noise were the main tasks left from the commissioning phase. Several SDI spectral time series with up to 300 individual spectra per day recovered the well-known solar 5-minute oscillation at a peak of 3 mHz (5.5min) with a disk-integrated radial-velocity amplitude of only 47 cm/s. Spectral atlases for 50 bright benchmark stars including the Sun were recently released to the scientific community, among them the ancient planet- system host Kepler-444. These data combine PEPSI’s high spectral resolution of R=250,000 with signal-to-noise ratio (S/N) of many hundreds to even thousands covering the entire optical to near-infrared wavelength range from 384 to 913 nm. Other early science cases were exoplanet transits including TRAPPIST-1, a spectrum of Boyajian's star that revealed strong and structured but stable ISM Na D lines, a spectrum of Oph allowing a redetermination of the ISM Li line doublet, and a first Doppler image of the young solar analog EK Dra that revealed starspots with solar-like penumbrae.

NEID is an ultra-stabilized, high-resolution, fiber-fed, spectrometer being built by a multi-institutional team for the 3.5 m WIYN telescope at Kitt Peak National Observatory, with a delivery date in 2019. The instrument is supported by the NN-EXPLORE program, a joint endeavor between NASA and the NSF to provide the exoplanet community with extreme ground-based Doppler radial velocity (RV) measurement capability. NEID's primary science objective is the discovery and characterization of terrestrial mass exoplanets, including follow-up of planets discovered by TESS and other spacecraft missions. Achieving these goals requires a multi-faceted approach that combines a state of the art Doppler instrument with a RV precision goal of 30 cm/s, a significantly improved understanding of the stellar radial velocity signal and intrinsic stellar variability, and large numbers of observations distributed optimally in time following guidelines refined over the past 25 years of RV exoplanet discovery. NEID uses a single-arm white pupil echelle optical design to produce R~100,000 spectra covering the complete wavelength range from 0.38 - 0.92 microns on a single 9k x 9k CCD. The optical bench and optics are stabilized with a state of the art temperature control system that achieves sub-mK stability, and are surrounded by a vacuum chamber that maintains 10^-7 Torr pressure or better. This extreme stability minimizes drift in the optics and optomechanical systems. Light is transfered from the telescope to the spectrometer using fiber-optic feeds that combine circular and octagonal fibers with a ball-lens double scrambler to provide high amounts of radial and azmuthal scrambling that minimize variations in the input illumination. These fibers interface with the WIYN telescope through a sophisticated new instrument port, which will provide atmospheric-dispersion correction and active tip-tilt to ensure precise and repeatable target positioning on the fiber. A three tiered calibration system utilizes a Laser Frequency Comb as the primary wavelength calibrator, while providing a stabilized etalon and ThAr and UNe Hollow-Cathode Lamps as high-reliability backup sources. An integrated exposure meter in the form of a low-resolution spectrometer measures precise chromatic exposure time centroids. A sophisticated data reduction pipeline that builds upon algorithms developed over decades of precision RV spectroscopy will automatically transform raw images and telemetry into RVs and other high-level data products, which will be served to users and the community through a NExScI portal. In this paper, we will provide an overview of the NEID project, including a progress update on the instrument integration and testing. We will also describe the WIYN operations plan, which is built around queue scheduled observations, and detail notional science programs that can be carried out with NEID, including the instrument team's GTO program. Finally, we will briefly discuss the impacts of stellar variability, which currently limit RV measurement precision well shy of the fundamental instrument limit, and which we and others are actively working to better understand and mitigate. Additional papers in this conference will describe the instrument subsystems in more detail.

The Habitable-Zone Planet Finder (HPF) is a stabilized, fiber-fed, NIR spectrometer recently commissioned at the 10m Hobby-Eberly telescope (HET). HPF has been designed and built from the ground up to be capable of discovering low mass planets around mid-late M dwarfs using the Doppler radial velocity technique. Novel apects of the instrument design include mili-kelvin temperature control, careful attending to fiber scrambling, and optics, mounting and detector readout schemes designed to minimize drifts and maximize the radial velocity precision. The optical design of the HPF is an asymmetric white pupil spectrograph layout in a vacuum cryostat cooled to 180 K. The spectrograph uses gold-coated mirrors, a mosaic echelle grating, and a single Teledyne Hawaii-2RG (H2RG) NIR detector with a 1.7-micron cutoff covering parts of the information-rich z, Y and J NIR bands at a spectral resolution of R~55,000. The use of 1.7 micron H2RG enables HPF to operate warmer than most other cryogenic instruments- with the instrument operating at 180K (allowing normal glasses to be used in the camera) and the detector at 120K. We summarize the engineering and commissioning tests on the telescope and the current radial velocity performance of HPF. With data in hand we revisit some of the design trades that went into the instrument design to explore the remaining tall poles in precision RV measurements in the near-infrared. HPF seeks to extend the precision radial velocity technique from the optical to the near-infrared, and in this presentation, we seek to share with the community our experience in this relatively new regime.

SPIRou is the new high resolution echelle spectropolarimeter and high-precision velocimeter, in the near infra- red, for the 3.6m Canada-France-Hawaii Telescope (CFHT Mauna Kea). This next generation instrument aims at detecting and characterizing Earth-like planets in the habitable zone of low-mass dwarfs and at investigating how magnetic fields impact star and planet formation. SPIRou consists of an achromatic polarimetric module coupled with a fluoride fiber link to a thermally-controlled cryogenic echelle spectrograph, and a Calibration Unit which can fed the light of hollow-cathod lamps, a radial velocity reference (Fabry-Pérot), or a cold source to the polarimeter and/or the spectrograph. Here we present a summary of the full performances obtained in laboratory tests carried in Toulouse (France), and the first results of the on-going commissioning at the CFHT. SPIRou covers a spectral range from 0.96 to 2.48 μm (YJHK domain) in one single exposure at a resolving power of 70 K, providing unpolarized and polarized spectra (with sensitivity 10 ppm) of stars, with a 10 15% peak throughput. Lab tests demonstrate that SPIRou is capable of achieving a relative radial velocity precision better than 0.2 m/s rms on timescales of 24 hr. Science operations of SPIRou are expected to start in 2018 S2, enabling significant synergies with major space and ground instruments such as the JWST, TESS, ALMA and later-on PLATO and the ELT.

MEGARA is the new generation IFU and MOS optical spectrograph built for the 10.4m Gran Telescopio CANARIAS (GTC). The project was developed by a consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) and UPM (Spain). The instrument arrived to GTC on March 28th 2017 and was successfully integrated and commissioned at the telescope from May to August 2017. During the on-sky commissioning we demonstrated that MEGARA is a powerful and robust instrument that provides on-sky intermediate-to-high spectral resolutions RFWHM ~ 6,000, 12,000 and 20,000 at an unprecedented efficiency for these resolving powers in both its IFU and MOS modes. The IFU covers 12.5 x 11.3 arcsec² while the MOS mode allows observing up to 92 objects in a region of 3.5 x 3.5 arcmin². In this paper we describe the instrument main subsystems, including the Folded-Cassegrain unit, the fiber link, the spectrograph, the cryostat, the detector and the control subsystems, and its performance numbers obtained during commissioning where the fulfillment of the instrument requirements is demonstrated.

On June 25th 2017, the new intermediate-resolution optical IFU and MOS of the 10.4-m GTC had its first light. As part of the tests carried out to verify the performance of the instrument in its two modes (IFU and MOS) and 18 spectral setups (identical number of VPHs with resolutions R=6000-20000 from 0.36 to 1 micron) a number of astronomical objects were observed. These observations show that MEGARA@GTC is called to fill a niche of high-throughput, intermediateresolution IFU and MOS observations of extremely-faint narrow-lined objects. Lyman-α absorbers, star-forming dwarfs or even weak absorptions in stellar spectra in our Galaxy or in the Local Group can now be explored to a new level. Thus, the versatility of MEGARA in terms of observing modes and spectral resolution and coverage will allow GTC to go beyond current observational limits in either depth or precision for all these objects. The results to be presented in this talk clearly demonstrate the potential of MEGARA in this regard.

We have recently commissioned a novel infrared (0:9-1:7 μm) integral field spectrograph (IFS) called the Wide Integral Field Infrared Spectrograph (WIFIS). WIFIS is a unique instrument that offers a very large field-of-view (5000 x 2000) on the 2.3-meter Bok telescope at Kitt Peak, USA for seeing-limited observations at moderate spectral resolving power. The measured spatial sampling scale is ~ 1 x 1" and its spectral resolving power is R ~ 2; 500 and 3; 000 in the zJ (0:9 - 1:35 μm) and Hshort (1:5 - 1:7 μm) modes, respectively. WIFIS's corresponding etendue is larger than existing near-infrared (NIR) IFSes, which are mostly designed to work with adaptive optics systems and therefore have very narrow fields. For this reason, this instrument is specifically suited for studying very extended objects in the near-infrared such as supernovae remnants, galactic star forming regions, and nearby galaxies, which are not easily accessible by other NIR IFSes. This enables scientific programs that were not originally possible, such as detailed surveys of a large number of nearby galaxies or a full accounting of nucleosynthetic yields of Milky Way supernova remnants. WIFIS is also designed to be easily adaptable to be used with larger telescopes. In this paper, we report on the overall performance characteristics of the instrument, which were measured during our commissioning runs in the second half of 2017. We present measurements of spectral resolving power, image quality, instrumental background, and overall efficiency and sensitivity of WIFIS and compare them with our design expectations. Finally, we present a few example observations that demonstrate WIFIS's full capability to carry out infrared imaging spectroscopy of extended objects, which is enabled by our custom data reduction pipeline.

The AAO’s TAIPAN instrument is a multi-object fibre positioner and spectrograph installed on the 1.2m UK-Schmidt telescope at Siding Spring Observatory. The positioner, a prototype for the MANIFEST positioner on the Giant Magellan Telescope, uses independently controlled Starbug robots to position a maximum of 300 optical fibres on a 32cm glass field plate (for a 6 degree field of view), to an accuracy of 5 microns (0.3 arcsec). The Starbug technology allows multi-object spectroscopy to be carried out with a minimum of overhead between observations, significantly decreasing field configuration time. Over the next 5 years the TAIPAN instrument will be used for two southern-hemisphere surveys: Taipan, a spectroscopic survey of 1x10^6 galaxies at z<0.3, and FunnelWeb, a stellar survey complete to Gaia G=12.5. In this paper we present an overview of the operational TAIPAN instrument: its design, construction and integration, and discuss the 2017 commissioning campaign and science verification results obtained in early 2018.

We present an update on the overall construction progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now that all the major fabrication contracts are in place. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been effected to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project has experienced some delays in procurement and now has first light expected for the middle of 2019.

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~ 1.6-2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project recently started undertaking the commissioning process of a subsystem at the Subaru Telescope side, with the integration and test processes of the other subsystems ongoing in parallel. We are aiming to start engineering night-sky operations in 2019, and observations for scientific use in 2021. This article gives an overview of the instrument, current project status and future paths forward.

We present an overview and status update of the 4MOST project at the Final Design Review. 4MOST is a major new wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope at the Paranal Observatory of ESO. Starting in 2022, 4MOST will deploy 2436 optical fibres in a 4.1 square degree field-of-view using a fibre positioner based on the tilting spine principle. The fibres will feed one high-resolution (R~20,000) and two low-resolution (R~5000) spectrographs that all have fixed configuration, 3-channel designs with identical 6k x 6k CCD detectors. Updated performance estimates will be presented based on components already manufactured and pre-production prototypes of critical subsystems. The 4MOST science goals are mostly driven by a number of large area, space-based observatories of prime European interest: Gaia and PLATO (Galactic Archeology and Stellar Physics), eROSITA (High-Energy Sky), and Euclid (Cosmology and Galaxy Evolution). Science cases based on these observatories, along with wide-area ground-based facilities such as LSST, VISTA and VST drive the ten Consortium Surveys covering a large fraction of the Southern sky, with bright time mostly devoted to the Milky Way disk and bulge areas and the Magellanic Clouds, and the dark/gray time largely devoted to extra-galactic targets. In addition there will be a significant fraction of the fibre-hours devoted to Community Surveys, making 4MOST a true general-purpose survey facility, capable of delivering spectra of samples of objects that are spread over a large fraction of the sky. The 4MOST Facility Simulator was created to show the feasibility of the innovative operations scheme of 4MOST with all surveys operating in parallel. The simulator uses the mock catalogues created by the science teams, simulates the spectral throughput and detection of the objects, assigns the fibres at each telescope pointing, creates pointing distributions across the sky and simulates a 5-year survey (including overhead, calibration and weather losses), and finally does data quality analyses and computes the science Figure-of-Merits to assess the quality of science produced. The simulations prove the full feasibility of running different surveys in parallel.

MIRADAS (Mid-resolution InfRAreD Astronomical Spectrograph) is the facility near-infrared multi-object echelle spectrograph for the Gran Telescopio Canarias (GTC) 10.4-meter telescope. MIRADAS operates at spectral resolution R=20,000 over the 1-2.5µm bandpass), and provides multiplexing (up to N=12 targets) and spectro-polarimetry. The MIRADAS consortium includes the University of Florida, Universidad de Barcelona, Universidad Complutense de Madrid, Instituto de Astrofísica de Canarias, Institut d'Estudis Espacials de Catalunya and Universidad Nacional Autonoma de Mexico, as well as partners at A-V-S (Spain), New England Optical Systems (USA), and IUCAA (India). MIRADAS completed its Final Design Review in 2015, and in this paper, we review the current status and overall system design for the instrument, with scheduled delivery in 2018. We particularly emphasize key developments in cryogenic robotic probe arms for multiplexing, a macro-slicer mini-IFU, an advanced cryogenic spectrograph optical system, and a SIDECAR-based array control system for the 1x2 HAWAII-2RG detector mosaic.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 square degrees will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We present an overview of the instrumentation, the main technical requirements and challenges, and the current status of the project.

After completion of its final-design review last year, it is full steam ahead for the construction of the MOONS instrument - the next generation multi-object spectrograph for the VLT. This remarkable instrument will combine for the first time: the 8 m collecting power of the VLT, 1000 optical fibres with individual robotic positioners and both medium- and high-resolution spectral coverage acreoss the wavelength range 0.65μm - 1.8 μm. Such a facility will allow a veritable host of Galactic, Extragalactic and Cosmological questions to be addressed. In this paper we will report on the current status of the instrument, details of the early testing of key components and the major milestones towards its delivery to the telescope.

Based on the success of the SAMI integral field spectrograph (IFS) instrument on the Anglo-Australian Telescope (AAT) the capacity for large IFS nearby galaxy surveys on the AAT is being substantially expanded with a new instrument called Hector. The high filling-fraction imaging fibre bundles ‘hexabundles’ of the type used on SAMI, are being enlarged to cover up to 30-arcsec diameter. The aim is to reach two effective radii on most galaxies, where the galaxy rotation curve flattens and >75% of the specific angular momentum of disk galaxies is accounted for. Driven by the key science case, Hector will have a 1.3A spectral resolution, enabling high-order stellar kinematics to be measured on a larger fraction of galaxies than with any other IFS instrument. Hector will be on sky in 2019. The first module of Hector, Hector-I, will have 21 hexabundles and >42 sky fibres to observe 20 galaxies and a calibration star simultaneously. It consists of new blue and red-arm spectrographs that have been designed at the Australian Astronomical Observatory (AAO; now called AAO-Macquarie), coupled to the new hexabundles and robotic positioner from AAO-USydney (formerly the Sydney Astrophotonics Instrumentation Laboratory, SAIL) at Sydney University. A novel robotic positioning concept will compensate for varying telecentricity over the 2-degree-field of the AAT to recoup the 20% loss in light at the edge of the field. Hector-I will survey 15,000 galaxies. Additional modules in the future would result in 30,000 galaxies. Hector will take integral field spectroscopy on galaxies with z<0.15 in the 4MOST WAVES-North and WAVES-South∗ regions. The WAVES data, which will come later, will give the environment metrics neces- sary to relate how local and global environments influence galaxy growth through gas accretion, star formation and spins measured with Hector. The WALLABY ASKAP† survey will trace HI gas across the Hector fields, which in combination with Hector will give a complete view of gas accretion and star formation.

The LAMOST completed its first five years of operation in June 2017, and 9 million low resolution spectra are obtained. The spectrographs have been upgraded in 2017, and the resolution can reach up to 7500(with 2/3 slit). In the midresolution mode, the wavelength can cover 495nm-535nm(blue band) and 630nm-680nm(red band). The LAMOST will carry out the middle resolution spectroscopic survey in September 2018, and 3 million middle resolution spectra will be obtained. This paper describes the requirements, optical design and mechanical design of the LAMOST-MRS (the LAMOST middle resolution spectrograph)

The Gemini Infrared Multi-Object Spectrograph (GIRMOS) is a powerful new instrument being built to facility- class standards for the Gemini telescope. It takes advantage of the latest developments in adaptive optics and integral field spectrographs. GIRMOS will carry out simultaneous high-angular-resolution, spatially-resolved infrared (1 - 2.4 µm) spectroscopy of four objects within a two-arcminute field-of-regard by taking advantage of multi-object adaptive optics. This capability does not currently exist anywhere in the world and therefore offers significant scientific gains over a very broad range of topics in astronomical research. For example, current programs for high redshift galaxies are pushing the limits of what is possible with infrared spectroscopy at 8 -10- meter class facilities by requiring up to several nights of observing time per target. Therefore, the observation of multiple objects simultaneously with adaptive optics is absolutely necessary to make effective use of telescope time and obtain statistically significant samples for high redshift science. With an expected commissioning date of 2023, GIRMOS’s capabilities will also make it a key followup instrument for the James Webb Space Telescope when it is launched in 2021, as well as a true scientific and technical pathfinder for future Thirty Meter Telescope (TMT) multi-object spectroscopic instrumentation. In this paper, we will present an overview of this instrument’s capabilities and overall architecture. We also highlight how this instrument lays the ground work for a future TMT early-light instrument.

The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical spectrographs (arrayed as 78 pairs, each with a pair of spectrographs) fed by 35,000 fibers, each 1.5 arcsec diameter, at the focus of the upgraded 10 m Hobby-Eberly Telescope (HET). VIRUS has a fixed bandpass of 350-550 nm and resolving power R~750. The fibers are grouped into 78 integral field units, each with 448 fibers and 20 m average length. VIRUS is the first example of large-scale replication applied to optical astronomy and is capable of surveying large areas of sky, spectrally. The VIRUS concept offers significant savings of engineering effort and cost when compared to traditional instruments. The main motivator for VIRUS is to map the evolution of dark energy for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), using 0.8M Lyman-alpha emitting galaxies as tracers. The VIRUS array has been undergoing staged deployment starting in late 2015. Currently, more than half of the array has been populated and the HETDEX survey started in 2017 December. It will provide a powerful new facility instrument for the HET, well suited to the survey niche of the telescope, and will open up large spectroscopic surveys of the emission line universe for the first time. We will review the current state of production, lessons learned in sustaining volume production, characterization, deployment, and commissioning of this massive instrument.

The Maunakea Spectroscopic Explorer (MSE) is replacement of the existing 3.6-m Canada France Hawaii Telescope into a dedicated wide field highly multiplexed fiber fed spectroscopic facility. MSE is capable of observing over four thousand science targets simultaneously in two resolution modes. The paper describes the unique instrument system capabilities and its components starting from the telescope prime focus and ending at the spectrograph suite. The instrument system components have completed their conceptual designs and they include a Sphinx positioner system, fiber transmission system, low/moderate resolution and high resolution spectrographs and a calibration system. These components will be procured separately and the Project is responsible for their integration and the overall system performance afterward. The paper describes from a system perspective the specific design and interface constraints imposed on the components given the extra interface and integration considerations.

In this paper we present the Australian Astronomical Observatory’s concept design for Sphinx - a fiber positioner with 4,332 “spines” on a 7.77mm pitch for CFHT’s Mauna Kea Spectroscopic Explorer (MSE) Telescope. Based on the Echidna technology used with FMOS (on Subaru) and 4MOST (on VISTA), the next evolution of the tilting spine design delivers improved performance and superior allocation efficiency. Several prototypes have been constructed that demonstrate the suitability of the new design for MSE. Results of prototype testing are presented, along with an analysis of the impact of tilting spines on the overall survey efficiency. The Sphinx fiber positioner utilizes a novel metrology system for spine position feedback. The metrology design and the careful considerations required to achieve reliable, high accuracy measurements of all fibers in a realistic telescope environment are also presented.

Multi-object spectrometers (MOSs) are astronomical instruments capable of accurately acquiring spectra of up to several hundreds of objects of interest in a single exposure. Digital micromirror devices (DMDs) have proven to be an excellent candidate for use as slit masks in both terrestrial and space-based MOSs because they are highly reliable and rapidly re-configurable. The Rochester Institute of Technology Multi-Object Spectrometer (RITMOS) is a terrestrial DMD-based MOS, which uses a newer generation DMD, with improved scattered light characteristics. RITMOS utilizes a 0.700 XGA DMD with a micromirror pitch of 13.68 microns and a micromirror flip angle of 12 degrees. By design, RITMOS covers the spectral range 3900 - 4900 angstroms, with a dispersion of 0.7 angstroms per pixel; the resolving power is R∼5300. Performance evaluation has been conducted both in the laboratory and on-sky. The results presented here show that DMD-based MOSs are highly capable instruments, offering great observational flexibility, while achieving excellent signal-to-noise ratios by optimally rejecting the sky background.

We present the opto-mechanical design of SAMOS, the SOAR Adaptive-Module Optical Spectrograph. SAMOS is a multi-object, reconfigurable-slit spectrograph designed to fully exploit the Ground Layer Adaptive Optics (GLAO) laser guide system of SOAR, i.e. the SOAR Adaptive Module (SAM). While it is designed to maximize sensitivity, it can also efficiently operate in regular seeing limited conditions. It will operate in the optical spectrum, covering a bandpass of 400 - 950 nm, in two exposures, utilizing four grims: two to produce low resolution spectra, i.e. R » 3000, as well as two narrow bandpass, high resolution spectra at R » 10, 000. The instrument uses a large-format Digital Micromirror Device (DMD), a programmable array of miniature mirrors, as a programmable slit to steer light from the telescope focal plane into either a spectroscopic arm or an imaging arm. The DMD can be reconfigured in seconds, allowing a vast range of slit widths and lengths; each being a multiple of mirrors wide and long. In SAMOS this facilitates the collection of up to as many as 200 spectra simultaneously, allowing a multitude of slit configurations, which can be optimized for seeing and science, and, at the same time, enables parallel science imaging of non-dispersed targets through a suite of broad and narrowband filters. SAMOS is a very compact instrument, by necessity. It attaches to the SOAR Adaptive Optics Module (SAM), fitting in a location with limited space, requiring a highly folded, compact optical design. This paper discusses the opto-mechanical design of SAMOS, including the overall system design as well as detailed descriptions of the optical mounts and mechanisms.

In this paper we will report on the status of the instrumentation project for the European Southern Observatory's Extremely Large Telescope (ELT). Three instruments are in the construction phase: HARMONI, MICADO and METIS. The multi-conjugate adaptive optics system for MICADO, MAORY, is also under development. Preliminary Design Reviews of all of these systems are planned to be completed by mid-2019. The construction of a laser tomographic module for HARMONI is part of "Phase 2" of the ELT: the design has been advanced to Preliminary Design level in order to define the interface to the HARMONI spectrograph. Preparations for the next instruments have also been proceeding in parallel with the development of these instruments. Conceptual design studies for the multi-object spectrograph MOSAIC, and for the high resolution spectrograph HIRES have been completed and reviewed. We present the current design of each of these instruments and will summarise the work ongoing at ESO related to their development.

The GMT-Consortium Large Earth Finder (G-CLEF) is an instrument that is being designed to exceed the state-of-the-art radial velocity (RV) precision achievable with the current generation of stellar velocimeters. It is simultaneously being designed to enable a wide range of scientific programs, prominently by operating to blue wavelengths (< 3500Å). G-CLEF will be the first light facility instrument on the Giant Magellan Telescope (GMT) when the GMT is commissioned in 2023. G-CLEF is a fiber-fed, vacuum-enclosed spectrograph with an asymmetric white pupil echelle design. We discuss several innovative structural, optical and control system features that differentiate G-CLEF from previous precision RV instruments.

MICADO will enable the ELT to perform diffraction limited near-infrared observations at first light. The instrument’s capabilities focus on imaging (including astrometric and high contrast) as well as single object spectroscopy. This contribution looks at how requirements from the observing modes have driven the instrument design and functionality. Using examples from specific science cases, and making use of the data simulation tool, an outline is presented of what we can expect the instrument to achieve.

With the successful completion of our preliminary design phase, we will present an update on all design aspects of the IRIS near-infrared integral field spectrograph and wide-field imager for the Thirty Meter Telescope (TMT). IRIS works with the Narrow Field Infrared Adaptive Optics System (NFIRAOS) to make observations at the diffraction limit of TMT at wavelengths between 0.84 and 2.4 microns. The imager has been expanded to a 34 arcsec field of view and the spectrograph has a wide range of filter and spectral format combinations with a contiguous field of view up to 112x128 spatial elements. Among the many challenges the instrument faces, and has tried to address in its design, are atmospheric dispersion up to 100 times the sampling scale, unprecedented saturation issues in crowded fields, and the need for integrated on-instrument wavefront sensors. But the scientific payoff is enormous and IRIS on TMT will open entirely new opportunities in all areas of astrophysical science.

The Mid-Infrared ELT Imager and Spectrograph (METIS) is one of three first light instruments on the ELT. It will provide high-contrast imaging and medium resolution, slit-spectroscopy from 3 – 19um, as well as high resolution (R ~ 100,000) integral field spectroscopy from 2.9-5.3µm. All modes observe at the diffraction limit of the ELT, by means of adaptive optics, yielding angular resolutions of a few tens of milliarcseconds. The range of METIS science is broad, from Solar System objects to active galactic nuclei (AGN). We will present an update on the main science drivers for METIS: circum-stellar disks and exoplanets. The METIS project is now in full steam, approaching its preliminary design review (PDR) in 2018. In this paper we will present the current status of its optical, mechanical and thermal design as well as operational aspects. We will also discuss the challenges of building an instrument for the ELT, and the required technologies.

We report the design evolution for the GMT Integral Field Spectrograph, (GMTIFS). To support the range of operating modes – a spectroscopic channel providing integral field spectroscopy with variable spaxel scales, and a parallel imaging channel Nyquist sampling the LTAO corrected field of view - the design process has focused on risk mitigation for the demanding operational tolerances. We summarise results from prototype components, confirming concepts are meeting the necessary specifications. Ongoing review and simulation of the scientific requirements also leads to new demonstrations of the science that will be made possible with this new generation of high performance AO assisted instrumentation.

When combined with the huge collecting area of the ELT, MOSAIC will be the most effective and flexible Multi-Object Spectrograph (MOS) facility in the world, having both a high multiplex and a multi-Integral Field Unit (Multi-IFU) capability. It will be the fastest way to spectroscopically follow-up the faintest sources, probing the reionisation epoch, as well as evaluating the evolution of the dwarf mass function over most of the age of the Universe. MOSAIC will be world-leading in generating an inventory of both the dark matter (from realistic rotation curves with MOAO fed NIR IFUs) and the cool to warm-hot gas phases in z=3.5 galactic haloes (with visible wavelenth IFUs). Galactic archaeology and the first massive black holes are additional targets for which MOSAIC will also be revolutionary. MOAO and accurate sky subtraction with fibres have now been demonstrated on sky, removing all low Technical Readiness Level (TRL) items from the instrument. A prompt implementation of MOSAIC is feasible, and indeed could increase the robustness and reduce risk on the ELT, since it does not require diffraction limited adaptive optics performance. Science programmes and survey strategies are currently being investigated by the Consortium, which is also hoping to welcome a few new partners in the next two years.

We discuss the latest developments of a spectrograph for the Giant Magellan Telescope. The instrument is designed to provide high throughput, moderate resolution, optical spectra for the telescope and be capable of flexible and rapid reconfiguration. The focal plane can be populated with custom slit masks or multiple fibers, allowing for observations of multiple objects simultaneously.

We present the results from the phase A study of ELT-HIRES, an optical-infrared High Resolution Spectrograph for ELT, which has just been completed by a consortium of 30 institutes from 12 countries forming a team of about 200 scientists and engineers. The top science cases of ELT-HIRES will be the detection of life signatures from exoplanet atmospheres, tests on the stability of Nature’s fundamental couplings, the direct detection of the cosmic acceleration. However, the science requirements of these science cases enable many other groundbreaking science cases. The baseline design, which allows to fulfil the top science cases, consists in a modular fiber- fed cross-dispersed echelle spectrograph with two ultra-stable spectral arms providing a simultaneous spectral range of 0.4-1.8 μm at a spectral resolution of ~100,000. The fiber-feeding allows ELT-HIRES to have several, interchangeable observing modes including a SCAO module and a small diffraction-limited IFU.

The Arrayed Wide-Angle Camera System (AWACS) is an astronomical wide-field imaging system that utilizes hundreds of replicated small optical units spread across the focal surface of two-mirror telescopes. The AWACS concept is completely different from the traditional monolithic lens-based corrector design and can potentially enable a compact, cost-effective, and high-performance wide-field corrector system for the Extremely Large Telescopes. In this paper, we detail some of the AWACS design features and the results from early laboratory prototype tests.

The Wide Field Optical Spectrometer (WFOS) is a seeing limited, multi-object spectrograph and first light instrument for the Thirty Meter Telescope (TMT) scheduled for first observations in 2027. The spectrograph will deliver a minimum resolution of R~5,000 over a simultaneous wavelength range of 310 nm to 1,000 nm with a multiplexing goal of between 20 and 700 targets. The WFOS team consisting of partners in China, India, Japan, and the United States has completed a trade study of two competing concepts intended to meet the design requirements derived from the WFOS detailed science case. The first of these design concepts is a traditional slit mask instrument capable of delivering R~1,000 for up to 100 simultaneous targets using 1 x 7 arc second slits, and a novel focal plane slicing method for R~5,000 on up to 20 simultaneous targets can be achieved by reformatting the 1 arc-second wide slits into three 0.3 arc-second slits projected next to each other in the spatial direction. The second concept under consideration is a highly multiplexed fiber based system utilizing a robotic fiber positioning system at the focal plane containing 700 individual collectors, and a cluster of up to 12 replicated spectrographs with a minimum resolution of R~5,000 over the full pass band. Each collecting element will contain a bundle of 19 fibers coupled to micro-lens arrays that allow for contiguous coverage of targets and adaptation of the f/15 telescope beam to f/3.2 for feeding the fiber system. This report describes the baseline WFOS design, provides an overview of the two trade study concepts, and the process used to down-select between the two options. Also included is a risk assessment regarding the known technical challenges in the selected design concept.

TMT’s wide field optical spectrograph is a multi-object, first-light instrument with broad continuous wavelength coverage (0.310 – 1.0 m) at a moderate spectral resolution of R = 5000. The international WFOS design team has recently completed the downselect of two design approaches: a slicer-based monolithic architecture and a fiber-based modular concept. We present here the end-to-end conceptual design for the fiber-based optical spectrograph. Included are the front-end focal reduction optics for coupling light into the fibers, the spectrograph collimator and camera optics, and the dispersive architecture for each color channel. The highly multiplexed fiber-WFOS presents a unique design challenge in keeping costs for the modular spectrographs low while maintaining performance gains afforded by the TMT, and in particular the TMT plus ground-layer adaptive optics (GLAO). A full performance analysis including predicted spectral resolution and throughput is presented for the design.

We present the first results using a new SCHOTT 1% narrow band filter in the near infrared for the CIRCE camera of the 10.4m GTC telescope. The goal of the project is to detect very distant galaxies at the dawn of the Universe. These remote and extremely faint galaxies are selected by their Ly-alpha emission. For this project SCHOTT manufactured a high transmission 11 nm narrow band filter which has been used in the fully cryogenic near-infrared camera CIRCE of the Gran Telescopio Canarias Telescope. A steep interference filter Bandpass with FWHM 11nm centered at 1254nm was coated on a fused silica substrate. The filter achieved excellent maximum transmission and deep out of band blocking. This was achieved by using magnetron sputtering for the filter coating process. We report on the spectral and interferometric results of the filter and the scientific results achieved with a first set of observations.

The design and performance of a three-channel image and long-slit spectrograph for the new 4-m telescope in China are described. The direct imaging covers a 3 arcmin by 3 arcmin field of view and a large wavelength range 370-1,600 nm, it has two optical channels and one near infrared channel with different filters. The spectrograph with a long slit is to provide two observing modes including the following spectral resolutions: R1000 and R5000. For dispersing optical elements it use volume-phased holographic grisms (VPHG) at each of the spectroscopic modes to simplify the camera system. The low resolution mode (R1000) is provided by consecutive observations with the spectral ranges: 360-860 nm, however it adopts only one VPHG for the first light. The spectral range of medium resolution mode (R5000) is 460- 750nm, it is constrained with the use of a 4k × 4k CCD detector of 15 μm pixel size. Peak efficient in the spectrograph are achieved to be higher than 50% in different resolution mode.

Coupling a high-contrast imaging instrument to a high-resolution spectrograph has the potential to enable the most detailed characterization of exoplanet atmospheres, including spin measurements and Doppler mapping. The high-contrast imaging system serves as a spatial filter to separate the light from the star and the planet while the high-resolution spectrograph acts as a spectral filter, which differentiates between features in the stellar and planetary spectra. The Keck Planet Imager and Characterizer (KPIC) located downstream from the current W. M. Keck II adaptive optics (AO) system will contain a fiber injection unit (FIU) combining a high-contrast imaging system and a fiber feed to Keck’s high resolution infrared spectrograph NIRSPEC. Resolved thermal emission from known young giant exoplanets will be injected into a single-mode fiber linked to NIRSPEC, thereby allowing the spectral characterization of their atmospheres. Moreover, the resolution of NIRSPEC (R = 37,500 after upgrade) is high enough to enable spin measurements and Doppler imaging of atmospheric weather phenomenon. The module was integrated at Caltech and shipped to Hawaii at the beginning of 2018 and is currently undergoing characterization. Its transfer to Keck is planned in September and first on-sky tests sometime in December.

The Simultaneous-color Wide-field Infrared Multi-object Spectrograph, SWIMS, is a first-generation near-infrared instrument for the University of Tokyo Atacama Observatory (TAO) 6.5m Telescope now being constructed in northern Chile. To utilize the advantage of the site that almost continuous atmospheric window appears from 0.9 to 2.5 μm, the instrument is capable of simultaneous two-color imaging with a field-of-view of 9.′6 in diameter or λ/▵λ 1000 multi-object spectroscopy at 0.9–2.5 μm in a single exposure. The instrument has been trans- ported in 2017 to the Subaru Telescope as a PI-type instrument for carrying out commissioning observations before starting science operation on the 6.5m telescope. In this paper, we report the latest updates on the instrument and present preliminary results from the on-sky performance verification observations.

An overview of the optical design for the SOXS spectrograph is presented. SOXS (Son Of X-Shooter) is the new wideband, medium resolution (R>4500) spectrograph for the ESO 3.58m NTT telescope expected to start observations in 2021 at La Silla. The spectroscopic capabilities of SOXS are assured by two different arms. The UV-VIS (350-850 nm) arm is based on a novel concept that adopts the use of 4 ion-etched high efficiency transmission gratings. The NIR (800- 2000 nm) arm adopts the ‘4C’ design (Collimator Correction of Camera Chromatism) successfully applied in X-Shooter. Other optical sub-systems are the imaging Acquisition Camera, the Calibration Unit and a pre-slit Common Path. We describe the optical design of the five sub-systems and report their performance in terms of spectral format, throughput and optical quality. This work is part of a series of contributions^1-9 describing the SOXS design and properties as it is about to face the Final Design Review.

We present the NIR spectrograph of the Son Of XShooter (SOXS) instrument for the ESO-NTT telescope at La Silla (Chile). SOXS is a R~4,500 mean resolution spectrograph, with a simultaneously coverage from about 0.35 to 2.00 μm. It will be mounted at the Nasmyth focus of the NTT. The two UV-VIS-NIR wavelength ranges will be covered by two separated arms. The NIR spectrograph is a fully criogenic echelle-dispersed spectrograph, working in the range 0.80- 2.00 μm, equipped with an Hawaii H2RG IR array from Teledyne, working at 40 K. The spectrograph will be cooled down to about 150 K, to lower the thermal background, and equipped with a thermal filter to block any thermal radiation above 2.0 μm. In this poster we will show the main characteristics of the instrument along with the expected performances at the telescope.

We report on the upgraded One Degree Imager (ODI) at the WIYN 3.5 meter telescope at the Kitt Peak Observatory after the focal plane was expanded by an additional seventeen detectors in spring 2015. The now thirty Orthogonal Transfer Array CCD detectors provide a total field of view of 40’ x 48’ on the sky. The newly added detectors underwent a design revision to mitigate reduced charge transfer efficiency under low light conditions. We discuss the performance of the focal plane and challenges in the photometric calibration of the wide field of view, helped by the addition of telescope baffles. In a parallel project, we upgraded the instrument’s three filter arm mechanisms, where a degrading worm-gear mechanism was replaced by a chain drive that is operating faster and with high reliability. Three more filters, a u’ band and two narrow band filters were added to the instrument’s complement, with two additional narrow band filters currently in procurement (including an Hα filter). We review the lessons learned during nearly three years of operating the instrument in the observatory environment and discuss infrastructure upgrades that were driven by ODI’s needs.

SPRAT1 is a low resolution (R ∼ 300) long-slit spectrograph operating in the optical range 400 – 800 nm. It employs a linear layout with deployable optics and can image a 7.5 × 1.8 arcmin field during target acquisition. SPRAT has successfully operated on the robotic 2-metre Liverpool Telescope (LT)² on La Palma since late 2014, with >1000 calibration arc spectra and acquisition images taken since installation. Reliable autonomous acquisition without human intervention requires stricter stability criteria to reliably locate a target object in a long-slit spectrograph. We describe methods used to characterise the mechanical repeatability in deployment of the slit and optical components using calibration arcs and standard star spectra, together with acquisition field images. The effect of the instrument orientation and annual temperature variations on the accuracy in locating a target in the imaging plane is characterised together with longer term drifts. The characterisation is compared with the initial design goals of the instrument and used to calculate correction coefficients.

Time variation of the atmospheric water vapor is an important problem to achieve accurate photometry in ground-based mid-infrared observations. Long-term (~ minutes or hours) variation has been already known, but short-term (~ seconds) variation has not been quantified in previous studies. We evaluate this short-term variation and the photometric error in the mid-infrared observations at the TAO site by using actual astronomical data. Estimated photometric errors are typically less than 1% but show 2-5% in two of fifteen cases. This suggests that the short-term variation of the water vapor is one of the factors which limit the photometric accuracy in ground based mid-infrared observations.

The LSST Camera focal plane comprises twenty-one raft tower modules (RTMs), each with nine CCD sensors and their associated electronics. RTMs are assembled at Brookhaven National Lab and shipped to SLAC National Lab, where they must be re-verified before being assembled into the full focal plane. The process for accepting an RTM at SLAC has been thoroughly documented, including unpacking a raft from its shipping container, verifying aliveness of the electrical connections, performing metrology and electro-optical testing in an environment similar to the full Camera, and finally storing the RTM until it can be installed into the LSST Camera

In the era of Extremely Large Telescopes, the current generation of 8-10m facilities are likely to remain competitive at far-blue visible wavelengths for the foreseeable future. High-efficiency (<20%) observations of the ground UV (300- 400 nm) at medium resolving power (R~20,000) are required to address a number of exciting topics in stellar astrophysics, while also providing new insights in extragalactic science. Anticipating strong demand to better exploit this diagnostic-rich wavelength region, we revisit the science case and instrument requirements previously assembled for the CUBES concept for the Very Large Telescope.

The 4.1-m SOAR telescope needs fast tip-tilt guiding and active correction of focus and astigmatism to reach good image quality allowed by the excellent site seeing. A concept of the new guider with a 2×2 wavefront sensor is presented. It uses the X-Y positioning mechanism of the current guider, while the pick-off arm, camera, and detector are replaced by the new hardware. The pick-off arm has 2 positive lenses to collimate the beam, with an internal focus adjustment to compensate for focus offset in the science instrument and for the field curvature. The 4 spots are formed by a mirror with slightly tilted segments, located near the camera. The detector is an EM CCD; guiding on stars as faint as V=17 mag is possible using the correlation algorithm for centroiding; aberrations are measured on the averaged images. Results of the on-sky tests of the new guider prototype are presented.

In order to accommodate new instrumentation arriving in early 2018, the Canada-France-Hawaii Telescope (CFHT) converted one of its coudé spectrograph rooms into a cleanroom. The new instrumentation required ISO 8 conditions with a desired performance of ISO 7. The turn-key solutions available all provide much higher levels of performance at prices well outside the budget of the project, so we modified the room using a more cost effective in-house approach. We discuss the requirements of the new instrumentation, new administrative rules and procedures, changes made to the room and new equipment, and the resulting performance.

The Mid-Infrared Multi-field Imager for gaZing at the UnKnown Universe (MIMIZUKU) is a mid-infrared camera and spectrograph developed as a first-generation instrument on the University of Tokyo Atacama Observatory (TAO) 6.5-m telescope. MIMIZUKU covers a wide wavelength range from 2 to 38 μm and has a unique optical device called Field Stacker which realizes accurate calibration of variable atmospheric transmittance with a few percent accuracy. By utilizing these capabilities, MIMIZUKU realizes mid-infrared long-term monitoring, which has not been challenged well. MIMIZUKU has three optical channels, called NIR, MIR-S, and MIR-L, to realize the wide wavelength coverage. The MIR-S channel, which covers 6.8–26 μm, has been completed by now. We are planning to perform engineering observations with this channel at the Subaru telescope before the completion of the TAO 6.5-m telescope. In this paper, we report the results of the laboratory tests to evaluate the optical and detector performances of the MIR-S channel. As a result, we confirmed a pixel scale of 0.12 arcsec/pix and a vignetting- free field of view of 2./0 1./8. The instrument throughputs for imaging modes are measured to be 20–30%. Those for N - and Q -band spectroscopy modes are 17 and 5%, respectively. As for the detector performance, we derived the quantum efficiency to be 40–50% in the mid-infrared wavelength region and measured the readout noise to be 3000–6000 electrons, which are larger than the spec value. It was found that this large readout noise degrades the sensitivity of MIMIZUKU by a factor of two.

We present the commissioning of an IFU based on image-slicers and a 2D-Field-of-View Scanning System (FoV-SS) for the GREGOR Infrared Spectrograph (GRIS). The prototype of the image-slicer has eight slices of 1.8 mm x 0.1 mm in Zerodur, covering an area of 20 arcsec². The FoV-SS, equipped with three Degrees of Freedom (DoF), allows to scan a region of 1 arcmin², feeding the image-slicer with different portions of the field of view. A batch of tests was done during the Assembly, Integration and Verification (AIV) at GREGOR telescope.

SOXS will be a unique spectroscopic facility for the ESO NTT telescope able to cover the optical and NIR bands thanks to two different arms: the UV-VIS (350-850 nm), and the NIR (800-1800 nm). In this article, we describe the design of the visible camera cryostat and the architecture of the acquisition system. The UV-VIS detector system is based on a e2v CCD 44-82, a custom detector head coupled with the ESO continuous flow cryostats (CFC) cooling system and the NGC CCD controller developed by ESO. This paper outlines the status of the system and describes the design of the different parts that made up the UV-VIS arm and is accompanied by a series of contributions describing the SOXS design solutions (Ref. 1–12).

The South African Astronomical Observatory (SAAO) is currently developing WiNCam, the Wide-field Nasmyth Camera, to be mounted on Lesedi, the observatory’s new 1-metre telescope. This paper discusses the design and results for the remotely-operated camera system. The camera consists of an E2V-231-C6 Back Illuminated Scientific Charge Coupled Device (CCD) sensor with 6144x6160 pixels, four outputs operating in non-inverted mode. This is to date the largest single chip CCD-system developed at SAAO. The CCD is controlled with a modified Inter-University Centre for Astronomy and Astrophysics (IUCAA) Digital Sampler Array Controller (IDSAC) utilizing digital correlated double sampling. The camera system will have full-frame and frame-transfer read out modes available with sub-windowing and pre-binning abilities. Vacuum through-wall PCB technology is used to route signals through the vacuum interface between the controller and the CCD. A thin, compact, 125x125mm aperture, sliding-curtain-mechanism shutter was designed and manufactured together with a saddle-type filter-magazine-gripper system. The CCD is cryogenically cooled using a Stirling Cooler with active vibration cancellation; CCD temperature control is done with a Lake Shore Temperature Controller. A Varian Ion Pump and Activated Charcoal are used to maintain good vacuum and to prolong intervals between vacuum pump down. The various hardware components of the system are connected using distributed software architecture, and a web-based GUI allows remote and scripted operation of the instrument.

The Next Generation Palomar Spectrograph (NGPS) is designed for Cassergrain focus of the Hale 200-inch telescope to replace the old Palomar Double Spectrograph (DBSP). NGPS have higher throughput, efficiency and realities spectrograph. NGPS is designed as three channels to cover the wavelength from 365nm to 1050nm with no spectral gap and delivers a resolving power with a 1.5” slit exceeding R=1800 overall the observable range. The peak efficiency of the whole throughput (from sky to detector) at the wavelength is 35.3% which is consistent with throughput achieved by some of the world’s most efficient spectrographs.

SOXS (Son of X-Shooter) will be the new medium resolution (R~4500 for a 1 arcsec slit), high-efficiency, wide band spectrograph for the ESO-NTT telescope on La Silla. It will be able to cover simultaneously optical and NIR bands (350-2000nm) using two different arms and a pre-slit Common Path feeding system. SOXS will provide an unique facility to follow up any kind of transient event with the best possible response time in addition to high efficiency and availability. Furthermore, a Calibration Unit and an Acquisition Camera System with all the necessary relay optics will be connected to the Common Path sub-system. The Acquisition Camera, working in optical regime, will be primarily focused on target acquisition and secondary guiding, but will also provide an imaging mode for scientific photometry. In this work we give an overview of the Acquisition Camera System for SOXS with all the different functionalities. The optical and mechanical design of the system are also presented together with the preliminary performances in terms of optical quality, throughput, magnitude limits and photometric properties.

MIMIZUKU (Mid-infrared Multi-field Imager for gaZing at the UnKnown Universe) is a near- to mid-infrared camera for the 6.5-m TAO (The university of Tokyo Atacama Observatory) telescope. To realize both the compactness of the instrument and the wide field of view of 2 arcmin, MIMIZUKU has unique reflective optics, which is composed of off-axis aspherical mirrors made of machined aluminum. These mirrors should be placed and aligned very precisely with the accuracy of < 0.01 mm and < 0.01 degrees. We performed the experiments to test whether MIMIZUKU optics works as designed at cryogenic temperature. We present the evaluation of imaging performance and the distortion on the focal plane of MIMIZUKU.

Washburn Astronomical Laboratories of the University of Wisconsin-Madison Astronomy Department is developing a near infrared (NIR) integral field spectrograph for the 11-meter Southern African Large Telescope (SALT). This instrument will extend SALT’s capabilities into the NIR, providing medium resolution spectroscopy over the wavelength range of 0.8 to 1.7 microns. The integral field unit (IFU) is optimized for sampling nearby galaxies with an on-sky hexagonal extent of 24 x 28 arcsec containing 217 fibers of 1.33 arcsec diameter (median SALT seeing is 1.5 arcsec). Two separate blocks of 15 sky fibers are adjustable to distances ranging 54 to 165 arcsec from the IFU. This spectrograph, formerly known as RSS-NIR, was originally designed to mount at prime focus coupled to an optical spectrograph through a dichroic beam-splitter. The need to simplify telescope operations at prime focus prompted its reconfiguration into a fiber-fed, cooled, bench spectrograph, resulting in lower instrumental thermal background with a separate cooled collimator, stabilization of the pupil illumination in the spectrograph due to the azimuthal scrambling properties of fibers, and higher throughput at short wavelengths. Field-flattening and sky subtraction with the existing slit spectrograph has been challenging due to SALT’s varying pupil as the instrument payload tracks across the fixed primary mirror during observations. Simulations show that fiber scrambling of the pupil will improve the achievable sky subtraction residuals by 1-2 orders of magnitude. In this paper we present an overview of the reconfigured spectrograph design, its improved expected performance, and the new science drivers for NIR integral field spectroscopy.

Skylines and associated background is and will become a major issue for the near-infrared instrumentation for large telescopes. Due to telescopes size in the future, the temporal variation of the sky background can become a real issue using standard techniques of sky subtraction (cross-beam switching, dithering, etc.), if we want to reach a precision below 1%. Only the understanding of the temporal behavior of sky background (in a short period of time) can help us, to better correct the sky background and minimize the final residual. Using ESO archives of two infrared IFU instruments at the VLT (X-Shooter and KMOS). We have studied the behavior of the sky background in two skyline-free region at 1.1 and 1.8 microns, the selected region were inspected visually to avoid small skylines that can affect the measures (See Flores et al., 2016). This analyze complete the study realized by Yang et al. (2012) in the optical region using FORS2 data. Preliminary analysis shows that the sky continuum background at 1.1 and 1.8 microns, in regions of 0.6x0.6 and 0.6x1.2 sq arcsec has temporal variation of 0.6 to 3% for consecutive exposure time of 900s and 600s, respectively. we also found that the variations of the bottom of the sky at 1.8 microns are 2 times more important than the variations at 1.2 microns. This result will be included in future simulations using standard sky subtraction techniques, in particular to reevaluate the performances of instruments aiming to detect ultra faint objects/ features.

We present the data reduction pipeline, MEAD, for Arizona Lenslets for Exoplanet Spectroscopy (ALES), the first thermal infrared integral field spectrograph designed for high-contrast imaging. ALES is an upgrade of LMIRCam, the 1 - 5 μm imaging camera for the Large Binocular Telescope, capable of observing astronomical objects in the thermal infrared (3 - 5 μm) to produce simultaneous spatial and spectral data cubes. The pipeline is currently designed to perform L-band (2.8 - 4.2 μm) data cube reconstruction, relying on methods used extensively by current near-infrared integral field spectrographs. ALES data cube reconstruction on each spectra uses an optimal extraction method. The calibration unit comprises a thermal infrared source, a monochromator and an optical diffuser designed to inject specific wavelengths of light into LBTI to evenly illuminate the pupil plane and ALES lenslet array with monochromatic light. Not only does the calibration unit facilitate wavelength calibration for ALES and LBTI, but it also provides images of monochromatic point spread functions (PSFs). A linear combination of these monochromatic PSFs can be optimized to fit each spectrum in the least-square sense via x² fitting.

The World Space Observatory--Ultraviolet (WSO--UV) is a Russian-Spanish space mission born as a response to the growing up demand for UV facilities by the astronomical community. WSO-UV mission will make observations with spectrographs and imagers in UV domain (115-310 nm). For many astrophysical tasks of the mission Core program high resolution spectroscopic observations (R = 50000) will require ground support spectroscopic observations in spectral domain of 300-1000 nm. For these purposes we are upgrading existing facilities of Special Astrophysical Observatory, including NES, ESPRI and CAES spectrographs, and installing new ones. Nesmith Echellè Spectrograph (NES) of 6-m telescope with its fused silica optics allows to get spectra with R=70000 in 310-800 nm spectral region. We estimate its instrumental polarization on the 3-th flat mirror. Echellè Spectrograph of PRImary focus (ESPRI) for faint object spectrapolarimetry with R=25000 is under construction now. The 1-m telescope will be equipped by Cassegrain echellè spectrograph CAES. Here we present detail information on such instrumentation and our recent achievements. This paper provides an information on instrumentation update.

We report on the upgrade of the fiber link of FIES, the high-resolution echelle spectrograph at the Nordic Optical Telescope (NOT). In order to improve the radial velocity (RV) stability of FIES, we replaced the circular fibers by octagonal and rectangular ones to utilize their superior scrambling performance. Two additional fibers for a planned polarimetry mode were added during the upgrade. The injection optics and the telescope front-end were also replaced. The first on-sky RV measurements indicate that the influence of guiding errors is greatly suppressed, and the overall RV precision of FIES has significantly improved.

The installation of fully-depleted Hamamatsu CCDs in GMOS-N in February/March 2017 marked the conclusion of the CCD upgrade project for the two Gemini Multi-Object Spectrographs. The corresponding upgrade for GMOS-S was completed in June/July 2014, so that both GMOS instruments are now operated with a detector array of three fully-depleted Hamamatsu CCDs. We present results from the commissioning of the GMOS-N Hamamatsu CCDs and discuss their on-sky performance. We provide a comparison of the GMOS-N and GMOSS detector parameters and summarize the main observing and data reduction strategies that apply to both detector arrays.

Characterization of an instrument’s detector is an essential part of assessing the overall performance and ca- pabilities of an instrument. We present our efforts to characterize the HAWAII-2RG detector on the imager component of the OSIRIS instrument at W. M. Keck Observatory. In particular, we will report the detector’s read noise, dark current, linearity, and persistence. We find a gain of 2.16 ± 0.34, in good agreement with Teledyne’s reported gain of 2.15. The maximum read noise of the detector is 23.4 ± 1.3 e^- decreasing with an increasing number of reads. We find an upper limit on the dark current of the detector to be < 0.021 e^-/pix/s. The detector is also linear to the 1% level up to 44,500 e^- and to the 5% level at 80,000 e^-. The maximum well depth is measured to be 119,000 e^-.

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a heavily modified Boeing 747SP aircraft, accommodating a 2.7 meter infrared telescope. This airborne observation platform operates at flight altitudes of up to 13.7 km (45,000 ft) and therefore allows a nearly unobstructed view of the visible and infrared universe at wavelengths between 0.3 µm and 1600 µm. The Focal Plane Imager (FPI+) is SOFIA’s main tracking camera. It uses a commercial, off-the-shelf camera with a thermoelectrically cooled EM-CCD. The back-illuminated sensor has a peak quantum efficiency greater than 95% at 550 nm and the dark current is as low as 0.01 e-/pix/sec. Since 2015, the FPI+ has been available to the community as a Facility Science Instrument, and can be used to observe stellar occultations by solar system objects such as dwarf planets, moons, asteroids, and comets, and transits of extra-solar planets. To date, SOFIA has conducted multi-channel observations of occultations, e.g. the occultation by Pluto in June of 2015 or the occultation by Triton in October 2017, using three instruments, HIPO and FLITECAM at the main instrument flange of the telescope, and the FPI+. This multi-wavelength sampling is important for enabling discrimination of particle sizes and constituents of hazes in the atmosphere of bodies such as Pluto and Triton, and the coma material of comets. Multi-wavelength observations also serve to allow us to place constraints on the chemical compositions of these formations. After the retirement of the two other instruments, the FPI+ is now SOFIA’s only remaining observing tool for occultations. In order to preserve some of the multi-color observing capability of the platform, we here discuss the addition of a second spectral channel to the FPI+. In a first upgrade step, a beamsplitter will split the incoming light and send it to two EMCCD cameras, one working in the ”blue”, e.g. SLOAN g’ band, and the other working in the ”red”, e.g. SLOAN i’ or z’ band. In a second upgrade step, the ”red” channel could be equipped with a NIR camera in order to provide a wider wavelength separation of the two bands. This will however require a modified dichroic coating on the tertiary (Nasmyth) mirror of the SOFIA telescope. This paper presents a preliminary design study of the opto-mechanical configuration of the dual channel FPI+.

LUCI1 and LUCI2 are a pair multi-mode, fully cryogenic near-infrared instruments installed at the Large Binoc- ular Telescope (LBT). The instruments provide imaging, long-slit and multi-object spectroscopy over a 4/ FoV in seeing-limited mode. Ground-layer AO (GLAO) correction for imaging and spectroscopy over the 4/ FoV is available using the ARGOS laser system, as well as diffraction-limited AO over a 30// FoV using the LBT first light AO (FLAO) system with natural guide stars. Internal flexure of the instrument is taken care of by passive and active flexure compensation. Image shifts in seeing-limited modes are compensated by a passive flexure con- trol algorithm using pre-defined look-up tables. For AO observations, passive compensation is replaced by active control. In the following, we present the details of the newly developed active flexure compensation algorithm for the LUCI instruments. We also describe some hardware modifications to the instruments and the results obtained with active flexure compensation.

A thermal-infrared polarimetric capability of the Infrared Camera and Spectrograph (IRCS) for the Subaru Telescope is described. A new half-wave retarder for the thermal-infrared band in 2–5 µm is introduced into the Waveplate Unit of the Nasmyth platform on the infrared side of the telescope to realize imaging- and low resolution spectro-polarimetry in that wavelength region. Through day-time calibrations using a wire-grid polarizer, the peak efficiency of the polarization is found to be 90-98% consistently in both imaging- and spectro- polarimetry in the thermal-infrared bands. In 2016 May and 2017 June, two engineering observing runs have been carried out to verify the on-sky performance.

The Son Of X-Shooter (SOXS)1 is a medium resolution spectrograph (R ~ 4500) proposed for the ESO 3.6m NTT. We present the optical design of the UV-VIS arm of SOXS which employs high efficiency ion-etched gratings used in first order (m = 1) as the main dispersers. The spectral band is split into four channels which are directed to individual gratings, and imaged simultaneously by a single three-element catadioptric camera. The expected throughput of our design is > 60% including contingency. The SOXS collaboration expects first light in early 2021. This paper is one of several papers presented in these proceedings_2-10 describing the full SOXS instrument.

We present the design and measured performance of the Aperture Wheel and the Pupil and Filter Wheel mechanisms for the NIX camera of the VLT/ERIS instrument. Both mechanisms were developed for high opto-mechanical precision and stability while operating at 70 K. We summarise the design constraints and considerations. Further, we have developed a dedicated cryo-test facility to allow measuring the position repeatability under nominal operational conditions. We demonstrate that the wheel mechanisms perform as designed and provide the measurement methodology and results of the opto-mechanical tolerances.

SOXS (Son of X-shooter) is a wide band, medium resolution spectrograph for the ESO NTT with a first light expected in early 2021. The instrument will be composed by five semi-independent subsystems: a pre-slit Common Path (CP), an Acquisition Camera (AC), a Calibration Unit (CU), the NIR spectrograph, and the UV-VIS spectrograph. In this paper, we present the mechanical design of the subsystems, the kinematic mounts developed to simplify the final integration procedure and the maintenance. The concept of the CP and NIR optomechanical mounts developed for a simple pre- alignment procedure and for the thermal compensation of reflective and refractive elements will be shown.

The GeMS/GSAOI pair has been in regular science operation since 2013 at the Gemini South telescope and regularly delivers close to diffraction limited imaging in the NIR bands over a wide field of view of 85" square. Although the original GeMS/GSAOI science cases intentionally did not specify any astrometric performance, the Gemini users community expressed a large interest into using it with this purpose. Both instruments are subject to gravity-induced flexures. GSAOI is often dismounted from the telescope in instrument exchanges, making a regular on-sky calibration strategy time prohibitive. In 2017, we installed a new GeMS calibration focal plane mask offering ~1600 pinhole sources with a position accuracy of ±25 μm equivalent to ±0.4 mas, which can be used to deliver distortion calibration. We evaluate the flexure effect in the GeMS/GSAOI pair and discuss how to facilitate the mask to calibrate intra-night distortion drifts.

We report design of acousto-optic imaging spectrometer for spectral and polarimetric photometry and commis- sioning of the instrument at 0.6-m F/12.5 telescope at the Southern Astronomical Station of Lomonosov Moscow State University. The spectrometer was operating over the spectral range 3800–5800 Å with the passband of 10 Å at the wavelength of 5000 Å The imaging spectrometer could be used for observations of objects with the minimum brightness of 12.5 mag (for 0.6-m telescope, 120 s exposition, and SNR∼10). Spatial resolution of the spectrometer was estimated better than 1.2”, and the field of view was ∼250”.

High-resolution infrared spectropolarimetry has many science applications in astrophysics. One of them is measuring weak magnetic fields using the Zeeman effect. Infrared domain is particularly advantageous as Zeeman splitting of spectral lines is proportional to the square of the wavelength while the intrinsic width of the line cores increases only linearly. Important science cases include detection and monitoring of global magnetic fields on solar-type stars, study of the magnetic field evolution from stellar formation to the final stages of the stellar life with massive stellar winds, and the dynamo mechanism operation across the boundary between fully- and partially-convective stars. CRIRES+ (the CRIRES upgrade project) includes a novel spectropolarimetric unit (SPU) based on polar- ization gratings. The novel design allows to perform beam-splitting very early in the optical path, directly after the tertiary mirror of the telescope (the ESO Very Large Telescope, VLT), minimizing instrumental polariza- tion. The new SPU performs polarization beam-splitting in the near-infrared while keeping the telescope beam mostly unchanged in the optical domain, making it compatible with the adaptive optics system of the CRIRES+ instrument. The SPU consists of four beam-splitters optimized for measuring circular and linear polarization of spectral lines in YJ and HK bands. The SPU can perform beam switching allowing to correct for throughput in each beam and for variations in detector pixel sensitivity. Other new features of CRIRES+, such as substantially increased wavelength coverage, stability and advanced data reduction pipeline will further enhance the sensitivity of the polarimetric mode. The combination of the SPU, CRIRES+ and the VLT is a unique facility for making major progress in understanding stellar activity. In this article we present the design of the SPU, laboratory measurements of individual components and of the whole unit as well as the performance prediction for the operation at the VLT.

Atmospheric composition provides essential markers of the most fundamental properties of giant exoplanets, such as their formation mechanism or internal structure. New-generation exoplanet imagers, like VLT/SPHERE or Gemini/GPI, have been designed to achieve very high contrast (< 15 mag) at small angular separations (<0.500) for the detection of young giant planets in the near-infrared, but they only provide very low spectral resolutions (R < 100) for their characterization. High-dispersion spectroscopy at resolutions up to 105 is one of the most promising pathways for the detailed characterization of exoplanets, but it is currently out of reach for most directly imaged exoplanets because current high-dispersion spectrographs in the near-infrared lack coronagraphs to attenuate the stellar signal and the spatial resolution necessary to resolve the planet. Project HiRISE (High-Resolution Imaging and Spectroscopy of Exoplanets) ambitions to develop a demonstrator that will combine the capabilities of two flagship instruments installed on the ESO Very Large Telescope, the high-contrast exoplanet imager SPHERE and the high-resolution spectrograph CRIRES+, with the goal of answering fundamental questions on the formation, composition and evolution of young planets. In this work, we will present the project, the first set of realistic simulations and the preliminary design of the fiber injection unit that will be implemented in SPHERE.

The Cherenkov Telescope Array (CTA) foresees, in its southern site (Chile), the implementation of up to 70 small-sized telescopes (SSTs), which will extend the energy coverage up to hundreds of TeV. It has been proposed that one of the first set of CTA SSTs will be represented by the ASTRI mini-array, which includes (at least) nine ASTRI telescopes. The endto-end prototype of such telescopes, named the ASTRI SST-2M, is installed in Italy and it is now completing the overall commissioning and entering the science verification phase. ASTRI telescopes are characterized by an optical system based on a dual-mirror Schwarzschild-Couder design and a camera at the focal plane composed of silicon photomultiplier sensors managed by a fast read-out electronics specifically designed. Based on a custom peak-detector mode, the ASTRI camera electronics is designed to perform Cherenkov signal detection, trigger generation, digital conversion of the signals and data transmission to the camera server. In this contribution we will describe the main features of the ASTRI camera, its performance and results obtained during the commissioning phase of the ASTRI SST-2M prototype in view of the ASTRI mini-array implementation.

CRIRES+ is the new high-resolution NIR echelle spectrograph intended to be operated at the platform B of VLT Unit telescope UT3. It will cover from Y to M bands (0.95-5.3um) with a spectral resolution of R = 50000 or R=100000. The main scientific goals are the search of super-Earths in the habitable zone of low-mass stars, the characterisation of transiting planets atmosphere and the study of the origin and evolution of stellar magnetic fields. Based on the heritage of the old adaptive optics (AO) assisted VLT instrument CRIRES, the new spectrograph will present improved optical layout, a new detector system and a new calibration unit providing optimal performances in terms of simultaneous wavelength coverage and radial velocity accuracy (a few m/s). The total observing efficiency will be enhanced by a factor of 10 with respect to CRIRES. An innovative spectro-polarimetry mode will be also offered and a new metrology system will ensure very high system stability and repeatability. Fiinally, the CRIRES+ project will also provide the community with a new data reduction software (DRS) package. CRIRES+ is currently at the initial phase of its Preliminary Acceptance in Europe (PAE) and it will be commissioned early in 2019 at VLT. This work outlines the main results obtained during the initial phase of the full system test at ESO HQ Garching.

We describe TCal, a mobile spectrophotometric calibration system that will be used to characterize the throughput as a function of wavelength of imaging systems at observatories around the world. TCal measurements will enhance the science return from follow-up observations of imaging surveys such as LSST (Large Synoptic Survey Telescope) and DES (Dark Energy Survey) by placing all tested imaging systems on a common photometric baseline. TCal uses a 1 nm bandpass tunable light source to measure the instrumental response function of imaging systems from 300 nm to 1100 nm, including the telescope, optics, filters, windows, and the detector. The system is comprised of a monochromator-based light source illuminating a dome flat field screen monitored by calibrated photodiodes, which allows determination of the telescope throughput as a function of wavelength. This calibration will be performed at 1-8m telescopes that expect to devote time towards survey follow-up. Performing the calibration on these telescopes will reduce systematic errors due to small differences in bandpass, making follow-up efforts more precise and accurate.

Washburn Astronomical Laboratories in the University of Wisconsin-Madison Astronomy Department is developing a near infrared (NIR) integral field spectrograph for the 11-meter Southern African Large Telescope (SALT). This instrument will extend SALT’s capabilities into the NIR, providing medium resolution spectroscopy over the wavelength range of 0.8 to 1.7 microns. Formerly known as RSS-NIR, this spectrograph was originally designed to mount at the prime focus of SALT and share a common collimator and spaceframe structure with the visible wavelength Robert Stobie Spectrograph (RSS-VIS). However, to maximize performance of both the instrument and telescope, its configuration has been changed into a fiber fed instrument located in the spectrometer room below the telescope7. This change necessitated the addition of several new components, including a separate collimator; a fiber integral field unit (IFU); a means to inject light from the telescope into the fibers; and a cooled enclosure to house the spectrograph, collimator, and pseudo-slit end of the fiber cable. The new collimator consists of four refractive elements, one of which is calcium fluoride, and requires a new lens barrel and support structure. The new fiber system incorporates a hexagonally arranged 217-fiber IFU and two mini-bundles containing 15 sky fibers each. The IFU is fabricated out of a two-part clam-shell stainless steel ferrule. The existing SALT fiber instrument feed (FIF) mechanism is adapted to position the IFU and sky bundles on sky, while a slave motion on flexure pivots ensures that the fibers remain telecentric. A 42-m protected fiber cable spans the distance between the telescope prime focus and the pseudo-slit in the spectrometer room. The cable is constructed out of four 25mm outer diameter flexible conduits. Within the conduit, each fiber is individually protected in its own Teflon tube. The route of the fiber cable through the telescope requires careful accommodation of controlled bending. The pseudo-slit comprises a line of mini v-groove blocks attached to the slit plate. The slit, collimator, and spectrograph are housed inside a 40 cold enclosure in the SALT spectrometer room. The cooling system, developed by Norlake Scientific to our specifications, carefully controls against thermal shock and humidity. This paper describes the design, integration, and laboratory verification of the reconfigured spectrograph system, as well as our experiences operating in a -40 ambient pressure environment.

Son Of X-Shooter (SOXS) is the new instrument for the ESO 3.5 m New Technology Telescope (NTT) in La Silla site (Chile) devised for the spectroscopic follow-up of transient sources. SOXS is composed by two medium resolution spectrographs able to cover the 350-2000 nm interval. An Acquisition Camera will provide a light imaging capability in the visible band. We present the procedure foreseen for the Assembly, Integration and Test activities (AIT) of SOXS that will be carried out at sub-systems level at various consortium partner premises and at system level both in Europe and Chile.

NIHTS is a first-generation instrument now in use on Lowell Observatory’s Discovery Channel Telescope. It is a nearinfrared prism spectrograph of the BASS design featuring high throughput and low dispersion that is intended for observations of faint solar system and astrophysical objects over the YJHK spectral range. An unusual feature is its ability to observe simultaneously with the Large Monolithic Imager, an optical CCD camera, by means of a dichroic fold mirror. This is particularly valuable for time-variable targets such as Kuiper Belt Objects, asteroids, exoplanet transits, and brown dwarfs. We describe its design details and performance both in the lab and on the telescope.

The integral field spectrograph configuration of the LMIRCam science camera within the Large Binocular Telescope Interferometer (LBTI) facilitates 2 to 5 µm spectroscopy of directly imaged gas-giant exoplanets. The mode, dubbed ALES, comprises magnification optics, a lenslet array, and direct-vision prisms, all of which are included within filter wheels in LMIRCam. Our observing approach includes manual adjustments to filter wheel positions to optimize alignment, on/off nodding to track sky-background variations, and wavelength calibration using narrow band filters in series with ALES optics. For planets with separations outside our 1”x1” field of view, we use a three-point nod pattern to visit the primary, secondary and sky. To minimize overheads we select the longest exposure times and nod periods given observing conditions, especially sky brightness and variability. Using this strategy we collected several datasets of low-mass companions to nearby stars.

The Calibration Unit (CU) is a subsystem of the Enhanced Resolution Imager and Spectrograph (ERIS), the newgeneration instrument for the Cassegrain focus of the ESO UT4/VLT, aimed at performing AO-assisted imaging and medium resolution spectroscopy in the 1-5 micron wavelength range. The ERIS-CU is aimed to providing both focal plane artificial sources and uniform illumination over the 0.4 - 2.4 micron wavelengh range, for purposes of calibration and technical check of the SPIFFIER spectrograph, the NIX camera and the AO Module. Some challenging aspects emerged during the detailed design phase, mainly related to the need to cover such a broad wavelength range while ensuring adequate photon rates, excellent image quality and high Strehl. The technical solutions adopted to achieve the final design goals are presented and their implementation during the construction phase are shown and discussed.

MegaCam is Canada-France-Hawaii Telescope’s (CFHT) one-degree wide-field optical imager with an array of 40 CCDs that has been in operation since 2003 and remains the most demanded instrument at CFHT with an oversubscription of 2.5 each semester. Large programs requiring hundreds of nights dominate the available observing time leaving little for PI programs. To accommodate the demand and to improve overall observing efficiency, we launched the MegaCam FAST project to reduce the data acquisition time.

WIRC+Pol is a newly commissioned low-resolution (R 100), near-infrared (J and H bands) spectropolarimetry mode of the Wide-field InfraRed Camera (WIRC) on the 200-inch Hale Telescope at Palomar Observatory. The instrument utilizes a novel polarimeter design based on a quarter-wave plate and a polarization grating (PG), which provides full linear polarization measurements (Stokes I, Q, and U ) in one exposure with no need for a polarimetric modulator. The PG also has high transmission across the J and H bands. The instrument is situated at the prime focus of an equatorially mounted telescope. As a result, the system only has one reflection in the light path and the instrument does not rotate with respect to the sky, which provides minimal and stable telescope induced polarization. A data reduction pipeline has been developed for WIRC+Pol to produce linear polarization measurements from observations, allowing, e.g., real-time monitoring of the signal-to-noise ratio of ongoing observations. WIRC+Pol has been on-sky since February 2017. Results from the first year commissioning data show that the instrument has a high dispersion efficiency as expected from the polarization grating. We discuss instrumental systematics we have uncovered in the data, their potential causes, along with calibrations that are necessary to eliminate them. We demonstrate the polarimetric stability of the instrument with RMS variation at 0.2% level over 30 minutes for a bright standard star (J = 8.7). While the spectral extraction is photon noise limited, polarization calibration between sources remain limited by systematics.

NESSI (New Mexico Exoplanet Spectroscopic Survey Instrument) was originally conceived, designed and built under a NASA NM-EPSCoR funded effort as a near-infrared multi-object spectrograph for characterizing exoplanet transits at the Magdalena Ridge Observatory. With the help of funding from JPL, we are moving NESSI to its new home on the Hale telescope in early 2018. Salient features of the New NESSI include a 6.5 arc minute field-of-view, low (R~250) or moderate (R~1100) spectral resolutions across J, H and/or K bands, the ability to stare at transits with high frame-rates, and finally a suite of on-board filters for imaging applications. We present the new design of NESSI, lessons learned in the refurbishment process, as well as an update for next steps in the process.

The Arizona Lenslet for Exoplanet Spectroscopy (ALES) has been conceived of as an integral field spectrograph (IFS) that can be integrated with the existing 1-5 micron imaging camera LBTI/LMIRcam. Retrofitting an IFS to an existing camera poses interesting optical design issues. We have developed four reflective magnifier designs to create the proper scale for each spaxel of the IFS across the operational wavelengths of ALES. The lenslet design utilizes the flexible nature of silicon etching to provide aberration correction of images across the field of view that are introduced by inserting these magnifiers into the existing LMIRcam optical system. Finally, direct vision prism designs have been developed to provide suitable dispersion modes for the reference science cases of ALES.

We will be upgrading the MMT Observatory’s (MMTO) Adaptive Optics (AO) system with a novel Pyramid Wavefront Sensor (PWFS). Our camera will utilize Leonardo’s SAPHIRA, a low-read-noise electron Avalanche Photodiode (eAPD) array. By observing natural guide stars in the near-infrared, we will improve the sky coverage at the MMTO by an order of magnitude. We have developed a compact cryostat that utilizes Sunpower’s CryoTel MT cryocooler to reduce the SAPHIRA’s dark current and thermal background radiation. Our camera’s cooling performance and cryocooler induced vibrations have been quantified and the results are presented here. Upon characterizing the laboratory performance of our camera at various reverse-bias voltages, this instrument will be integrated with MMTO’s adaptive optics system. The successful implementation of this wavefront sensor will pave the way for future applications using this technology in AO systems of extremely large telescopes.

Gemini Observatory is committed to providing its community with the best possible competitive instrumentation suite given technological and budget constraints. This paper provides an update on our strategy to keep our instrumentation suite competitive, examines both our current funded upgrade projects and our future enhancements. The Observatory operates 4 facility instruments plus 1 AO system at each telescope. Next year it will incorporate a new facility instrument, will start building a major workhorse instrument for the next decade, and will complete the upgrade of the AO systems. We also run three major upgrades of workhorse instruments and a long-term program to support user motivated upgrades. Gemini also expanded the use of telescope time in procuring new instruments and supporting instrument upgrades. We expect these approaches will allow the Observatory to continue to grow the overall capabilities while being even more responsive to community needs.

Son of X-Shooter (SOXS) will be a high-efficiency spectrograph with a mean Resolution-Slit product of 4500 (goal 5000) over the entire band capable of simultaneously observing the complete spectral range 350-2000 nm. It consists of three scientific arms (the UV-VIS Spectrograph, the NIR Spectrograph and the Acquisition Camera) connected by the Common Path system to the NTT and the Calibration Unit. The Common Path is the backbone of the instrument and the interface to the NTT Nasmyth focus flange. The light coming from the focus of the telescope is split by the common path optics into the two different optical paths in order to feed the two spectrographs and the acquisition camera. The instrument project went through the Preliminary Design Review in 2017 and is currently in Final Design Phase (with FDR in July 2018). This paper outlines the status of the Common Path system and is accompanied by a series of contributions describing the SOXS design and properties after the instrument Preliminary Design Review.

We have developed the near-infrared high-spatial resolution imaging and spectro-polarimetric modes with the laser guide adaptive optics system (AO188) and the Infrared Camera and Spectrograph (IRCS) of the 8.2-m Subaru telescope. A LiNbO₃ Wollaston prism (as dual beam analyzer) and focal plane masks were installed into the camera section of the IRCS cryostat, enabling us to perform the low- and medium-resolution grism spectropolarimetry (λ/Δλ = 100-1960) as well as the imaging-polarimetry, in conjunction with a half-wave retarder, which had been introduced for the HiCIAO instrument originally, at the front of the AO188 system. The designed wavelength coverage of the Wollaston prism is 0.8-5 μm, although the polarimetry at the 0.95-2.5 μm region is presented in this paper because of the limitations on the current retarder and the dichroic beam splitter of AO188. The focal plane masks, which are reflecting mirror or slits made with tungsten carbide, provide two or four rectangular focal plane apertures with an individual field of view of 4.4 arcsec × 21 arcsec or 4.4 × 54 arcsec for the imaging-polarimetry, or two or four slits with a width of 0.10, 0.15, 0.225, and 0.60 arcsec and a length of 4.4 arcsec for the spectro-polarimetry. The Wollaston prism and polarimetry masks were installed on June and July 2013, and the polarimetric modes had the first light on October 2013. The polarization efficiency is 88-96% and 55-80% at maximum for the imaging- and spectro-polarimetry, respectively, and it depends heavily on the angle of image rotator of AO188. The measured instrumental polarization, which is introduced by the telescope tertiary mirror mainly, is 0.3-0.7%. We describe the design and current performance of the polarimetric function in the near-infrared region.

SCORPIO (Spectrograph and Camera for Observation of Rapid Phenomena in the Infrared and Optical) is the new workhorse instrument for the Gemini South Telescope in Chile. Originally proposed in response to the Gen4#3 solicitation, SCORPIO is a unique fast-multicolor imager and ultra-wide band spectrograph capable of rapid exposures for high time-resolution images and spectra. SCORPIO consists of 8 separate channels (corresponding to the standard wavebands g, r, i, z, Y, H, J, K) that can operate with different exposure times. Each channel can be used in imaging or long-slit mode, with independent readout timing. In this report we illustrate the detectors, the control systems, and the observing modes that will be available with SCORPIO.

We present results from a cryogenic characterization of the grating vector Apodizing Phase Plate (gvAPP) coro- nagraph that will be used in the upcoming instrument ERIS (Enhanced Resolution Imager and Spectrograph) at the VLT. ERIS consists of a 1-5 μm imager (NIX) and a 1 2.5 μm integral field spectrograph (SPIFFIER), both fed by the Adaptive Optics Facility of UT4 to yield diffraction-limited spatial resolution. A gvAPP coronagraph will be included in the NIX imager to enable high-contrast imaging observations, which will be particularly powerful for the direct imaging of exoplanets at L and M bands (~3-5 μm) and will compliment the current capabilities of VLT/SPHERE and surpass the capabilities of VLT/NACO. We utilize the near-infrared test bench of the Star and Planet Formation group at ETH Zurich to measure key properties of the gvAPP coronagraph at its operating wavelengths and under the vacuum/cryogenic (~70 K) conditions of the future ERIS instrument.

After more than 4 years of operation it’s expected that the Gemini Planet Imager (GPI) will move from Gemini South (GS) to the Gemini North (GN) telescope sometime in 2019. Though both telescopes are almost identical at a hardware and software level there are subtle differences. With the accrued knowledge from operations from both a software and hardware point of view we will be addressing the following subjects: Changes in software on the telescope control level to interface with the similar system at GN, changes in the user interface for both instrument operation, proposal management, and observation preparations by a PI. Adjustments and requirements to interface at a hardware level with cooling and power requirements, and changes in the hardware configuration of network interfaces. We also show the results from vibration measurements at both telescopes and these measurements indicate that the vibrations will not be an issues when moving from GS to GN. Using more than 600h of observations and performance measurements and weather conditions at GS, and correlating with several years of weather monitoring at Mauna Kea we show what improvements in performance we can expect. We expect a significant improvement in performance due to the less turbulent atmosphere at GN, with post-processed contrast improving by a factor of 1.3–2.6.

More than half of the stars in the solar neighborhood reside in binary/multiple stellar systems, and recent studies suggest that gas giant planets may be more abundant around binaries than single stars. Yet, these multiple systems are usually overlooked or discarded in most direct imaging surveys, as they prove difficult to image at high-contrast using coronographs. This is particularly the case for compact binaries (less than 1’’ angular separation) with similar stellar magnitudes, where no existing coronagraph can provide high-contrast regime. Here we present preliminary results of an on-going Palomar pilot survey searching for low-mass companions around ~15 young “challenging” binary systems, with angular separation as close as 0’’3 and near-equal K-band magnitudes. We use the Stellar Double Coronagraph (SDC) instrument on the 200-inch Telescope in a modified optical configuration, making it possible to align any targeted binary system behind two vector vortex coronagraphs in cascade. This approach is uniquely possible at Palomar, thanks to the absence of sky rotation combined with the availability of an extreme AO system, and the number of intermediate focalplanes provided by the SDC instrument. Finally, we expose our current data reduction strategy, and we attempt to quantify the exact contrast gain parameter space of our approach, based on our latest observing runs.

The Phase-Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) is a promising corona- graphic device for direct detection of exoplanets with complex segmented telescope apertures. This concept features the bright idea of generating a pupil apodization by reflection on two mirrors whose wavefront maps are specifically optimized, and a complex focal plane mask. In this paper, we report on the design, specifications, and manufacturing of such a coronagraph for the SPEED facility (Segmented Pupil Experiment for Exoplanet Detection) struggled for deep contrast at small angular separation with complex telescope aperture.

The Gemini Planet Imager (GPI) is the dedicated high-contrast imaging facility, located on Gemini South, designed for the direct detection and characterization of young Jupiter mass exoplanets. In 2019, Gemini is considering moving GPI from Gemini South to Gemini North. Analysis of GPI's as-built performance has highlighted several key areas of improvement to its detection capabilities while leveraging its current capabilities as a facility class instrument. We present the proposed upgrades which include a pyramid wavefront sensor, broadband low spectral resolution prisms and new apodized-pupil Lyot coronagraph designs all of which will enhance the current science capabilities while enabling new science programs.

The instrument IRDIS on ESO/VLT-SPHERE allows for observations in polarimetry of circumstellar disks in the near infrared. Since circumstellar disks light is partially linearly polarized by the reflection of the star light on its surface, the DPI mode (Dual Polarimetry Imaging) allows us to recover the intensity and the angle of polarization leading to morphology and dust size studies of these disks. We have developed a new method to reduce the IRDIS-DPI data based on an inverse approach method. This method is based on an optimization using the electric field (Jones Matrices) rather than the intensity (Mueller matrices) and relies on the inverse approach (i.e. fitting a model of the data to the observed dataset) which is significantly less biased and more efficient at minimizing instrumental artefacts. We describe, in this paper, this new method and we compare it to the state of the art methods. Using two IRDIS-DPI datasets we also demonstrate its ability to reconstruct polarized intensities maps and the angle of polarization.

ERIS is a diffraction limited thermal infrared imager and spectrograph for the Very Large Telescope UT4. One of the science cases for ERIS is the detection and characterization of circumstellar structures and exoplanets around bright stars that are typically much fainter than the stellar diffraction halo. Enhanced sensitivity is provided through the combination of (i) suppression of the diffraction halo of the target star using coronagraphs, and (ii) removal of any residual diffraction structure through focal plane wavefront sensing and subsequent active correction. In this paper we present the two coronagraphs used for diffraction suppression and enabling high contrast imaging in ERIS.

The HiCIBaS (High-Contrast Imaging Balloon System) project aims at launching a balloon borne telescope up to 36km to test high contrast imaging equipment and algorithms. The payload consists of a off the shelf 14-inch telescope with a custom-built Alt-Az mount. This telescope provides lights to two sensors, a pyramidal low order wave front sensor, and a coronagraphic wavefront sensor. Since the payload will reach its cruise altitude at about midnight mission, two target stars have been designated for observations, Capella as the night target, and Polaris as the early morning target. Data will be collected mainly on the magnitude of atmospheric and gondola’s turbulences, the luminosity of the background. The whole system is already built and ready to ship to Timmins for the launch in mid-August 2018.

The TIKI instrument is a next generation 10-micron cryogenic extreme adaptive optics (ExAO) imager being designed for the Gemini South telescope. Its goal is to detect the thermal emission of Earth-like planets in orbit around Alpha Centauri A or B. TIKI is also a prototype for future TMT instruments capable of imaging Earth- like planets around a larger star sample, and performing low spectral resolution characterization to search for biomarkers on detected planets. The science module will operate at cryogenic temperature in order to minimize thermal background, dominant in the 10-micron wavelength range. The instrument will use Adaptive Optics, a vortex coronagraph, focal plane wavefront sensing, and advanced post-processing techniques to reach a 1E-7 contrast in less than 200 hours of observing time. It aims to be background-limited in the 2-5λ/D zone, which corresponds to the habitable zone around the two Sun-like stars of the Alpha Centauri system. In this paper, we give an overview of the project goals, present TIKI's conceptual optical design, and summarize preliminary simulation results.

SHARK-NIR is one of the forthcoming instruments of the Large Binocular Telescope second generation instruments. Due to its coronagraphic nature, coupled with low resolution spectroscopy capabilities, it will be mainly devoted to exoplanetary science, but its FoV of 18 x 18 arcsec and very high contrast imaging capabilities will allow to exploit also other intriguing scientific cases. The instrument has been conceived and designed to fully exploit the exquisite adaptive optics correction delivered by the FLAO module, which will be improved with the SOUL upgrade, and will implement different coronagraphic techniques, with contrast as high as 10-6 up to 65 mas from the star. Despite the wavelength range of SHARK-NIR is 0.96-1.7 um, the instrument is designed to work in synergy with SHARK-VIS and with LMIRcam, on board of LBTI. The contemporary acquisition from these instruments will extend the wavelength coverage from M band down to the visible radiation. The physical location of the instrument, at the entrance of LBTI, imposes dimensional constraints to the instrument, which had been kept very compact. The folded optical design includes more than 50 optical elements, among which 4 Off-Axis Parabolas, 1 Deformable Mirror for the compensation of the Non Common Path Aberrations from the FLAO Wavefront Sensor, 2 detectors and 3 different kinds of coronagraph: Gaussian Lyot, Shaped Pupil and Four Quadrant Pupil Mask. Most of these optics are located onto an optical bench 500 x 400 mm, which makes SHARK-NIR an extremely dense instrument. This, together with the presence of 4 off-axis parabolas and of coronagraphs, such as the Four Quadrant, poorly tolerant to misalignments, requires a careful alignment and test phase, which needs the fine adjustement of many hundreds of degrees of freedom. We will give here an overview of the opto-mechanical layout of SHARK-NIR and of the identified alignment procedure, mostly optical, planned to take place in 2018.

The High Contrast spectroscopy testbed for Segmented Telescopes (HCST) is being developed at Caltech. It aims at addressing the technology gap for future exoplanet imagers and providing the U.S. community with an academic facility to test components and techniques for high contrast imaging, focusing on segmented apertures proposed for future ground-based (TMT, ELT) and space-based telescopes (HabEx, LUVOIR). We present an overview of the design of the instrument and a detailed look at the testbed build and initial alignment. We offer insights into stumbling blocks encountered along the path and show that the testbed is now operational and open for business. We aim to use the testbed in the future for testing of high contrast imaging techniques and technologies with amongst with thing, a TMT-like pupil.

SHARK-VIS, the LBT forthcoming high-contrast imager, is undergoing its fabrication phase and will see its first light in Q4-2019. By exploiting the outstanding performance of the LBT SOUL adaptive optics in the range of wavelength from 400 to 1000 nm, the instrument is expected to provide breakthrough science results in different fields, from exoplanets detection and characterization, to star formation with resolutions around 15mas and a contrast larger than 1e-5 at 100mas of separation. This will be possible thanks to the unprecedented performances of the LBT extreme AO system and the instrument fast-frame-rate acquisition as already demonstrated by preliminary tests on-sky. In this contribution, we will review the main technical aspects of the instrument and present the current project status.

The physics of molecular vibration causes absorption spectra of atmospheric molecules to be a group of approximately periodic fine lines. This is fortuitous for detecting exoplanet biosignificant molecules, since it approximately matches the periodic sinusoidal transmission of an interferometer. The series addition of a 0.6 cm interferometer with a dispersive spectrograph creates moire patterns. These enhance detection by several orders of magnitude for initially low resolution spectrographs. We simulate the Gemini Planet Imager integral field spectrograph observing a telluric spectrum of native resolutions 40 and 70 for 1.65 and 2 micron bands– too low to resolve the fine lines. The interferometer addition increases the detectability of the molecular signal, relative to photon noise, to a level similar to a R=4400 (at 1.65 micron) or R=3900 (at 2 micron) spectrograph.

Long-term synoptic observations of the Sun in different wavelength regions are essential to understand its secular behavior. Such observations have proven very important for discovery of 11 year solar activity cycle, 22 year magnetic cycle, polar field reversals, Hale’s polarity law, Joy’s law, that helped Babcock and Leighton to propose famous solar dynamo model. In more recent decades, the societal impact of the secular changes in Sun’s output has been felt in terms of solar inputs to terrestrial climate-change and space-weather hazards. Further, it has been realized that to better understand the activity phenomena such as flares and coronal mass ejections (CMEs) one needs synoptic observations in multiple spectral lines to enable tomographic inference of physical parameters. Currently, there are both space and ground based synoptic observatories. However, given the requirements for the long-term stability and reliability of such synoptic datasets, ground-based facilities are more preferable. Also, the ground based observatories are easy to maintain or upgrade while detailed and frequent calibrations are easily possible. The only ground-based facility that currently provides full-disk velocity and magnetic field maps of the Sun around the clock and at good cadence, is the Global Oscillations Network Group (GONG) network of National Solar Observatory (NSO) which is operational since the mid 90s. Due to its aging instrumentation, operating for nearly three decades, and new requirements to obtain multiwavelength observations, a need is felt in the solar community to build a next generation synoptic observatory network. A group of international observatories have come together under the auspices of SOLARNET program, funded by European Union (EU), to carryout a preliminary design study of such a synoptic solar observing facility called “SPRING”, which stands for Solar Physics Research Integrated Network Group. In this article we will present concept of SPRING and the optical design concept of its major instruments.ts.

Mt. Abu Faint Object Spectrograph and Camera-Pathfinder (MFOSC-P) is an instrument currently under development for PRL 1.2m Optical-Near Infrared Telescope at Mt. Abu. It is a pathfinder instrument for a bigger and more complex next generation instrument on upcoming PRL 2.5m telescope. MFOSC-P has been conceptualized as a general purpose user’s instrument with sufficient ease in its operation. It offers options for both the imaging as well spectroscopy within the same optical chain in visible waveband (4500-8500 angstroms). The optics has been designed to provide ‘seeing limited imaging’ in astronomy standard Bessell’s B, V, R and I filters. Three modes of spectroscopy with resolutions (λ/Δλ) 2000, 1000 and 500 around 6500, 5500 and 6000 angstroms are achieved with plane reflection gratings. The mechanical system of the instrument has been designed and successfully evaluated for its structural integrity using finite element analysis. Here we present the optical and opto-mechanical designs of the instrument, which have been successfully developed in house under several existing technical constraints. The results of finite element analysis of the instrument are also presented.

We present the mechanical device used to install the Raft Tower Modules (RTMs) into the cryosat of the camera for the Large Synoptic Survey Telescope (LSST). In an RTM, the charge-coupled devices (CCDs) are packaged into a 3 x 3 Raft Sensor Assembly (RSA) and coupled to a Raft Electronics Crate (REC). An RTM weighs ~10 kg, is roughly 500 mm tall, and has a 126.5 mm-square footprint at the CCDs. The grid array which supports the RTM in the cryostat has a center-to-center distance of 127 mm. One of the key challenges for installing the RTMs in the 500 μm gap between CCDs of adjacent modules - contact between adjacent CCDs is strictly forbidden.

The Zwicky Transient Facility (ZTF) is a next-generation, optical, synoptic survey that leverages the success of the Palomar Transient Factory (PTF). ZTF has a large science focal plane (SFP) that needs to be aligned such that all portions of the CCDs are simultaneously placed in focus to optimize the survey’s efficiency. The SFP consists of 16 large, wafer-scale science CCDs, which are mosaicked to achieve 47 deg2 field of view. The SFP is aligned by repositioning each CCD based on the measured height map, which is a map of the camera’s z position at which each portion of the CCD is in focus. This height map is measured using on-sky stellar images in order to recreate the optical path that will be used throughout the survey. We present our technique for placing the SFP in focus, which includes two different methods to measure the height map of the SFP. The first method measures the height at which a star is in focus by fitting a parabola to each star’s photometric width as the star is moved in and out of focus. The second method measures the height by decomposing a defocused star into its image moments. We will discuss the strengths and limitations of each method and their outputs. By repositioning the CCDs, we were able to reduce the standard deviation of the height map from 33 to 14microns, which improved the survey’s speed by ∼ 81%.

We report on the acousto-optic spectral imaging system designed for speckle imaging observations and interferometry. The setup is based on a non-collinear paratellurite acousto-optic tunable filter (AOTF). Breadboard prototype of the system with an in-house fabricated AOTF has been designed and commissioned. The prototype spectral range covers the band from 3600 to 5800 Å. Arbitrary spectral transmission function synthesis of the AOTF was applied. The AOTF spectral transmission bandwidth is programmable in the range from 44 to 875 cm⁻¹ (12.5–250Å at the wavelength of 5050Å). The AOTF is synchronized with the CCD readout and can be used as a global electronic shutter with on/off switching time of 12 μs. The exposure is adjusted as any integer multiple of 4.5 μs.

This paper presents the design, fabrication and metrology results and the assembly and verification process of the LSST camera ceramic optical bench structure utilizing the unique manufacturing features of HB-Cesic technology. The optical bench assembly consists of a rigid “Grid” that supports individual raft plates, upon which the CCD sensor assemblies are mounted by way of a rigid kinematic support system. This structure allows it to meet stringent requirements for the focal plane planarity and thermal and mechanical stability.

The Fast automatic spectrograph for transient (FAST) is a valuable tool to classify resources and better characterize variable sources. FAST is a low resolution spectrograph with multiple resolving power modes (R ∼ 300 and 1000 at 6500 Å) in the VIS-UV range and with to capability to work in imaging mode. The spectrograph consist of a collimating mirror, reflective gratings, and a five-lenses design camera that offers a field of view of 10 arcmin when working in imaging mode. The instrument will be installed in the PROMPT-7 telescope which is able to operate without human intervention for the follow-up of time-variable sources. In this work, the optical design of the spectrograph, the telescope specifications, and the objects under study will be discussed.

MOPTOP is a new polarimeter design for the Liverpool Telescope, which aims to provide a wide field of view with high temporal resolution and multi-colour capability using a combination of a half wave plate, a polarizing beamsplitter and multiple sCMOS cameras. Here we present the optical design of a single-band prototype. We use a combination of commercial achromat and photographic camera lenses to obtain an image quality (100% encircled energy) of < 1.5 arcsec across a 7x7 arcmin field of view and a wavelength range of 400-800nm.

High-speed optical photometry is characterizing man made satellites and space debris in Earth orbit. Commercially available Electron Multiplying CCD (EMCCD) imagers and cameras are driving a renaissance in this field, with several new instruments under development. The Steward Observatory Chimera Photometer provides simultaneous three-color photometry in the Sloan r’, i’, and z’ bands over a wide field of view. The design is optimized for the Steward Observatory Kuiper 1.58 m Telescope, although other telescopes can be supported with the exchange of the wide-field collimator. In this paper, the design and first light performance of the instrument is presented.

The LSST Camera focal plane will be constructed with 21 144-Mpixel modules (“Raft Tower Module”, RTM). An extensive operational test is performed to confirm the integrity of all connections and to verify the basic functionality. Each RTM undergoes at least four connectivity tests. A python script communicates with Java- based control software and performs the test. A final script parses the test data and generates a PDF report. The report includes a summary PASS/FAIL table, several hundred current, voltage and temperature parameters, and images taken with the CCD array at room temperature.

Data collected with ground-based telescopes accounts for the overwhelming majority of astrometric observations of mainbelt and near-Earth asteroids. Earth’s atmosphere subjects these measurements to random error from seeing and to systematic bias from differential color refraction (DCR). The DCR bias when observing solar-illuminated targets with nonuniform spectral reflectances and using non-solar-analog stars as fiducials can be several tens of milliarcseconds, even at low airmass. The direction of DCR bias is aligned with local vertical at the observing telescope and its varying orientation in inertial space masks its signature in aggregate error analysis performed in inertial coordinates. Until recently, DCR effects of tens of milliarcseconds were dominated by the hundreds of milliarcseconds of systematic bias present in astrometric star catalogs. Improvements in the accuracy of catalogs beginning in 2015 with the 30 milliarcsecond URAT1 catalog, the 2017 publication of the 25 milliarcsecond UCAC5 catalog, and the forthcoming sub-milliarcsecond GAIA catalog have lowered the error floor on achievable accuracy to the point where DCR is now the dominant systematic bias in data taken from the ground. DCR bias depends on the spectral quantum efficiency of the observing instrument, the spectral reflectance of the target, and the spectral types of the fiducial stars. To realize the benefit of star catalogs accurate below the 30 milliarcsecond level, spectroscopic measurements of asteroids and fiducial stars are necessary to correct for DCR bias. We analyze archival observations of asteroids with known spectral types and present new findings with our own highvolume observations of GPS and GLONASS satellites and the asteroids 4179 Toutatis and 3122 Florence reduced using the URAT1 and UCAC5 catalogs to show that DCR, rather than catalog bias, is now unambiguously the dominant source of systematic error in ground-based astrometry. Our observations of 3122 Florence with the r’ and i’ passbands exhibit vertical residuals more than 100 milliarcseconds beyond what we predict using published reflectance spectra. We attribute the discrepancy between prediction and measurement to the high sensitivity of predicted DCR bias to the slope of the asteroid’s spectral reflectance within the r’ and i’ passbands and caution against relying on narrow passbands alone to mitigate DCR bias. We derive requirements for measurements of instrument spectral quantum efficiency and asteroid spectral reflectance necessary to compensate for DCR to a level commensurate with the accuracy of modern catalogs. The instrument passband must be well-sampled, and while a spectral resolution of 75 nm is sufficient on average when using an unfiltered silicon detector, a resolution of 10 nm is required to ensure worst-case astrometric accuracy of 25 milliarcseconds when observing asteroids with Sloan passbands down to zenith distances of 75 degrees. Systematic biases of tens of milliarcseconds correspond to kilometers of instantaneous cross-range error when observing asteroids. For certain geometries, that error builds with more data rather than averaging out. We examine all likely Earthimpact scenarios and find that when an asteroid approaches from inside 1 AU and forces ground-based observations to occur at large zenith distances, lack of DCR compensation results in impact point predictions that are biased significantly away from their true locations. We present hypothetical NEO discovery scenarios where at fewer than four months before impact, the bias in impact point estimates derived from available ground-based data is many hundreds of kilometers beyond the five-sigma formal uncertainty of the estimate.

Spatial Heterodyne Spectroscopy (SHS) is a relatively novel interferometric technique similar to Fourier transform spectroscopy and shares design similarities with a Michelson Interferometer. An Imaging detector is used at the output of a SHS to record the spatially heterodyned interference pattern. The spectrum of the source is obtained by Fourier transforming the recorded interferogram. The merits of the SHS -its design, including the lack of moving parts, compactness, high throughput, high SNR and instantaneous spectral measurements - makes it suitable for space as well as ground observatories. The small bandwidth limitation of the SHS can be overcome by building it in tunable configuration (Tunable Spatial Heterodyne Spectrometer(TSHS)). In this paper, we describe the wavelength calibration of the tunable SHS using a Halogen lamp and Andor monochromator setup. We found a relation between the fringe frequency and the wavelength.

In a dual-frequency liquid crystal (DFLC), when the frequency of the applied voltage is more than a critical value (fc), the dielectric anisotropy of the material changes from positive to negative. This causes the director to switch its orientation from parallel to the field (for f < fc), to perpendicular to it (f < fc). Hence DFLC can be used in modulating the light by switching the frequency of an externally applied voltage. We present in this work about application of DFLCs in full Stokes polarimetery. A polarization modulator has been worked out based on two DFLCs and two static retarders. The combination of DFLCs’ switching and static retarders are chosen such that more or less equal weightage is given to all the Stokes parameters. Initial results on the optimization of position angles of the modulators are presented towards the goal of achieving polychromatic modulator in the wavelength range 600-900 nm.

Our contribution intends to present the obtained performances of the NƎSIE instrument, a new near-infrared fiber-fed spectrograph developed at the University of Liège. This instrument was developed, aligned and tested at the Centre Spatial de Liège and first light was achieved in October 2017. This paper will go through the alignment process and optical performance verification to eventually introduce the first light observations. The final location of NƎSIE will be the TIGRE telescope located in La Luz, Mexico. The observational data provided by this instrument will help several research groups from the University of Liège to study massive stars. In particularly, evolution models will be improved through the comparison of the collected spectra with theoretical models. This collaboration will therefore contribute to a better understanding of massive stars and the mechanisms that take place within these extraordinary objects.

Detecting polarization of the light reflected from an exoplanet requires extremely high-precision polarimeters and highaccuracy calibration techniques. The polarimetric precision of a few parts per million (ppm), approaching the photon noise, was demonstrated for the Sun and bright distant stars by several groups and instruments. However, the accuracy of absolute polarimetric calibration strongly depends on the polarimeter design and observing conditions, which results in largely unknown systematic errors hindering the exoplanet polarization detection. Here we discuss some of the crucial aspects of exoplanet polarimetric data acquisition, e.g., effects of seeing, sky polarization, telescope polarization, etc. We simulate examples of polarimetric measurements with various levels of random and systematic errors. They demonstrate that sparse measurements (ten or less) and unknown systematic errors can hinder exoplanet signal detection even when the signal is significantly larger than the polarimetric precision. We discuss various approaches which help improve random errors (precision) and mitigate systematic errors (accuracy) caused by various effects. We also discuss the performance of polarimeters with different designs and indicate their strengths and weaknesses in terms of precision and accuracy.

The Transiting Exoplanet Survey Satellite (TESS, launched early 2018) is expected to find a multitude of new transiting planet candidates around the nearest and brightest stars. Timely high-precision follow-up observations from the ground are essential in confirming and further characterizing the planet candidates that TESS will find. However, achieving extreme photometric precisions from the ground is challenging, as ground-based telescopes are subject to numerous deleterious atmospheric effects. Beam-shaping diffusers are emerging as a low-cost technology to achieve hitherto unachievable differential photometric precisions from the ground. These diffusers mold the focal plane image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, imperfect guiding, and telescope-induced variable aberrations seen in defocusing. In this paper, we expand on our previous work (Stefansson et al. 2017; Stefansson et al. 2018), providing a further detailed discussion of key guidelines when sizing a diffuser for use on a telescope. Furthermore, we present our open source Python package iDiffuse which can calculate the expected PSF size of a diffuser in a telescope system, along with its expected on-sky diffuser-assisted photometric precision for a host star of a given magnitude. We use iDiffuse to show that most (~80%) of the planet hosts that TESS will find will be scintillation limited in transit observations from the ground. Although iDiffuse has primarily been developed to plan challenging transit observations using the diffuser on the ARCTIC imager on the ARC 3.5m Telescope at Apache Point observatory, iDiffuse is modular and can be easily extended to calculate the expected diffuser-assisted photometric precisions on other telescopes.

RHEA is a compact high-resolution single-mode spectrograph that can easily be produced in larger quantities as budgets allow. The instrument will be housed in a temperature-stabilized vacuum chamber which is surrounded by several layers of thermal shielding. The optical design employs cost-effective commercially available compo- nents, a cooled CMOS detector, and a double-fiber input which permits simultaneous wavelength calibration.

S4EI (Spectral Sampling with Slicer for Stellar and Extragalactical Instrumentation) is a new concept for extending Multichannel Subtractive Double Pass (ie S4I - Spectral Sampling with Slicer for Solar Instrumentation) to night-time astronomy. The Multichannel Subtractive Double Pass (MSDP) spectrographs have been widely used in solar spectroscopy because of their ability to provide an excellent compromise between field of view and the spatial and spectral resolutions. Compared with other spectrographs, MSDP can deliver simultaneous monochromatic images without any time-scanning requirements (as the standard Fabry-Perot), with limited loss of flux. Spatial resolution is the same as for an Imager given by the telescope: it can be very high. It is based on new generation reflecting plane image slicers working with large apertures specific to night-time telescopes. The resulting design could be potentially very attractive and innovative for different domains of astronomy, e.g., the simultaneous spatial mapping of accurately flux-calibrated emission lines between OH sky lines in extragalactic astronomy or the simultaneous imaging of stars, exoplanets and interstellar medium. The determination of physical and chemical properties of galaxies needs to observe several emission lines at different wavelengths. The combination of these lines gives access to the distribution in dust, star formation rate, metallicity, the kinematics or even to the electron density of the gas in the galaxies. The spatial resolution of MSDP allows, like the 3D or integral field spectrographs the construction of spatial distribution maps. The advantage of S4EI is that by measuring simultaneously the different lines, the relative errors of the flux calibration between the different wavelengths of the lines are potentially limited by the uncertainty of the calibration source used, which is expected to significantly reduce the associated errors and thus increase the precision and accuracy of estimates.

We present the concept of a new Fabry-Perot instrument called BTFI-2, which is based on the design of another Brazilian instrument for the SOAR Telescope, the Brazilian Tunable Filter Imager (BTFI). BTFI-2 is designed to be mounted on the visitor port of the SOAR Adaptive Module (SAM) facility, on the SOAR telescope, at Cerro Pach´on, Chile. This optical Fabry-Perot instrument will have a field of view of 3 x 3 arcmin, with 0.12 arcsec per pixel and spectral resolutions of 4500 and 12000, at H-alpha, dictated by the two ICOS Fabry-Perot devices available. The instrument will be unique for the study of centers of normal, interacting and active galaxies and the intergalactic medium, whenever spatial resolution over a large area is required. BTFI-2 will combine the best features of two previous instruments, SAM-FP and BTFI: it will use an Electron Multiplication detector for low and fast scanning, it will be built with the possibility of using a new Fabry-Perot etalon which provides a range of resolutions and it will be light enough to work attached to SAM, and hence the output data cubes will be GLAO-corrected.

The Bench for Optical Testing (BOT) is a test stand that will be used for metrology and optical testing of the Large Synoptic Survey Telescope (LSST) Camera CCD sensors, immediately after the integration step where the sensors are installed into the Cryostat to form the LSST’s 3.2 gigapixel, 640mm diameter focal plane. The BOT uses existing methods to economically verify sensor performance, including measurement of focal plane flatness, CCD sensor spacing, gain stability, cross-talk, flat field images, response in each filter band, and dark level. This paper describes the requirements, design, and preliminary test results for the BOT test equipment.

The Gondola for High-Altitude Planetary Science (GHAPS) project is a balloon-borne astronomical observatory designed operate in the UV, Visible, and near-mid IR spectral region. The GHAPS Optical Telescope Assembly (OTA) is designed around a one meter aperture narrow field-of-view telescope with near-diffractionlimited performance. GHAPS will utilize Wallops Arc-Second Pointing System (WASP) for pointing the OTA with an accuracy of 1 arc second or better. WASP relies heavily on a self-contained star tracker assembly to determine the OTA line of sight. Preliminary structural analysis indicates that potential misalignments could be present between the OTA line of sight and the star tracker FOV center during the expected flight conditions that could compromise GHAPS pointing accuracy. In response the GHAPS project undertook a trade study to resolve the following issues: (1) estimate the worst case long-term (or bias) pointing misalignments for the GHAPS opto-mechanical configuration, (2) examine the need for additional hardware to correct pointing errors, and (3) determine the best hardware and software implementation to do so. Quantitative comparisons of performance and qualitative estimates of other factors such as mass, volume, power consumption, and cost are combined into an overall assessment of potential solutions. Results are discussed and a recommended implementation is given that is optimized to best achieve pointing performance goals, while minimizing impact to the design, cost, and resources of the GHAPS project.

Although there are a large number of known exoplanets, there is little data on their global atmospheric properties. Phase-resolved spectroscopy of transiting planets – continuous spectroscopic observation of planets during their full orbits – probes varied depths and longitudes in the atmospheres thus measuring their three-dimensional thermal and chemical structure and contributing to our understanding of their global circulation. Planets with characteristics suitable for atmospheric characterization have orbits of several days, so phase curve observations are highly resource intensive, especially for shared use facilities. The Exoplanet Climate Infrared TElescope (EXCITE) is a balloon-borne near-infrared spectrometer designed to observe from 1 to 5 μm to perform phaseresolved spectroscopy of hot Jupiters. Flying from a long duration balloon (LDB) platform, EXCITE will have the stability to continuously stare at targets for days at a time and the sensitivity to produce data of the quality and quantity needed to significantly advance our understanding of exoplanet atmospheres. We describe the EXCITE design and show results of analytic and numerical calculations of the instrument sensitivity. We show that an instrument like EXCITE will produce a wealth of quality data, both complementing and serving as a critical bridge between current and future space-based near infrared spectroscopic instruments.

The Pulsed All-sky Near-infrared Optical Search for ExtraTerrestrial Intelligence (PANOSETI) is an instrument program that aims to search for fast transient signals (nano-second to seconds) of artificial or astrophysical origin. The PANOSETI instrument objective is to sample the entire observable sky during all observable time at optical and near-infrared wavelengths over 300 - 1650 nm. The PANOSETI instrument is designed with a number of modular telescope units using Fresnel lenses (~0.5m) arranged on two geodesic domes in order to maximize sky coverage. We present the prototype design and tests of these modular Fresnel telescope units. This consists of the design of mechanical components such as the lens mounting and module frame. One of the most important goals of the modules is to maintain the characteristics of the Fresnel lens under a variety of operating conditions. We discuss how we account for a range of operating temperatures, humidity, and module orientations in our design in order to minimize undesirable changes to our focal length or angular resolution.

We present overall specifications and science goals for a new optical and near-infrared (350 - 1650 nm) instru- ment designed to greatly enlarge the current Search for Extraterrestrial Intelligence (SETI) phase space. The Pulsed All-sky Near-infrared Optical SETI (PANOSETI) observatory will be a dedicated SETI facility that aims to increase sky area searched, wavelengths covered, number of stellar systems observed, and duration of time monitored. This observatory will offer an “all-observable-sky” optical and wide-field near-infrared pulsed tech- nosignature and astrophysical transient search that is capable of surveying the entire northern hemisphere. The final implemented experiment will search for transient pulsed signals occurring between nanosecond to second time scales. The optical component will cover a solid angle 2.5 million times larger than current SETI targeted searches, while also increasing dwell time per source by a factor of 10,000. The PANOSETI instrument will be the first near-infrared wide-field SETI program ever conducted. The rapid technological advance of fast-response optical and near-infrared detector arrays (i.e., Multi-Pixel Photon Counting; MPPC) make this program now feasible. The PANOSETI instrument design uses innovative domes that house 100 Fresnel lenses, which will search concurrently over 8,000 square degrees for transient signals (see Maire et al. and Cosens et al., this conference). In this paper, we describe the overall instrumental specifications and science objectives for PANOSETI.

RHEA is a single-mode ´echelle spectrograph designed to be a replicable and cost effective method of undertaking precision radial velocity measurements. The instrument has a novel fiber feed with an integral field unit injecting into a grid of single-mode fibers reformatted to form a pseudo-slit, increasing throughput and enabling highspatial resolution observations when operating behind Subaru and the SCExAO adaptive optics system. The past 18 months have seen a replacement cable constructed for the instrument to address modal noise caused by closely packed fibers with similar path lengths. Here we detail the cable fabrication procedure, design improvements, increased precision in meeting the required sub-micron optical tolerances, throughput gains, and known remaining issues.

The Evryscope is a two-dozen-camera gigapixel-scale robotic telescope, which continuously images 8,000 square degrees in 2-minute exposures. The photometric performance reaches 5-10 millimag levels on a bright stars, depending on cadence, and on fainter objects is sufficient to detect planets around nearby cool main sequence stars and a host of other objects including eclipsing binaries, stellar activity, and microlensing events. The telescope also provides fast cadence observations necessary for detecting minute time-scale exoplanet transits, which would occur around small, compact host stars including white dwarfs and hot subdwarfs. The Evryscope South has been collecting data continuously since deployment to CTIO in mid-2015, and has produced millions of images and 100s of terabytes of data. Evryscope North is under construction and will be deployed to Mt. Laguna observatory in partnership with San Diego State University (SDSU) in late 2018. We present the instrument design, construction, solutions to unique challenges, results of ongoing surveys including searches for exoplanets in exotic star systems, a gas giant exoplanet candidate, low-mass stellar companion discoveries, and stellar activity characterization.

We propose a novel instrument design to greatly expand the current optical and near-infrared SETI search pa- rameter space by monitoring the entire observable sky during all observable time. This instrument is aimed to search for technosignatures by means of detecting nano- to micro-second light pulses that could have been emitted, for instance, for the purpose of interstellar communications or energy transfer. We present an instru- ment conceptual design based upon an assembly of 198 refracting 0.5-m telescopes tessellating two geodesic domes. This design produces a regular layout of hexagonal collecting apertures that optimizes the instrument footprint, aperture diameter, instrument sensitivity and total field-of-view coverage. We also present the optical performance of some Fresnel lenses envisaged to develop a dedicated panoramic SETI (PANOSETI) observatory that will dramatically increase sky-area searched (pi steradians per dome), wavelength range covered, number of stellar systems observed, interstellar space examined and duration of time monitored with respect to previous optical and near-infrared technosignature finders.

Discussion of a optical design for an Eight Channel Imager/Polarimeter is presented. The design will cover the optical and Near Infrared(NIR) wavelengths from 330nm to 2400nm in a simultaneous acquisition mode for eight distinct broad bands. The simultaneous acquisition provides capabilities to study unique events such as supernovae, Gamma Ray Bursts(GRBs), and occultations. It also increases the efficiency of long term monitoring programs such as the study of blazars. The selection of the wavelength bands were specifically chosen to match the Sloan Digital Sky Survey(u0, g0, r0, i0,z0) and the 2MASS(J,H,K) catalogs.

The limits to the angular resolution has, during the latest 70 years, been obtainable from the ground only through extremely expensive adaptive optics facilities at large telescopes, and covering extremely small spatial areas per exposure. Atmospheric turbulence therefore limits image quality to typically 1 arcsec in practice. We have developed a new concept of ground-based imaging instrument called GravityCam capable of delivering significantly sharper images from the ground than is normally possible without adaptive optics. The acquisition of visible images at high speed without significant noise penalty has been made possible by advances in optical and near IR imaging technologies. Images recorded at high speed can be aligned before combination and can yield a 3-5 fold improvement in image resolution, or be used separately for high-cadence photometry. Very wide survey fields are possible with widefield telescope optics. GravityCam is proposed to be installed at the 3.6m New Technology Telescope (NTT) at the ESO La Silla Observatory in Chile, where it will greatly accelerate the rate of detection of Earth sized planets by gravitational microlensing. GravityCam will also improve substantially the quality of weak shear studies of dark matter distribution in distant clusters of galaxies and provide a vast dataset for asteroseismology studies. In addition, GravityCam promises to generate a unique data set that will help us understand of the population of the Kuiper belt and possibly the Oort cloud.

Next-generation infrared astronomical instrumentation for ground-based and space telescopes could be based on MOEMS programmable slit masks for multi-object spectroscopy (MOS). MOS is used extensively to investigate astronomical objects optimizing the Signal-to-Noise Ratio (SNR): high precision spectra are obtained and the problem of spectral confusion and background level occurring in slitless spectroscopy is cancelled. Fainter limiting fluxes are reached and the scientific return is maximized both in cosmology, in galaxies formation and evolution, in stellar physics and in solar system small bodies characterization. We are developing a 2048 x 1080 Digital-Micromirror-Device-based (DMD) MOS instrument to be mounted on the 3.6m Telescopio Nazionale Galileo (TNG) and called BATMAN. A two-arm instrument has been designed for providing in parallel imaging and spectroscopic capabilities. BATMAN will be mounted on the folded Nasmyth platform of TNG. Thanks to its compact design, high throughput is expected. The two arms with F/4 on the DMD are mounted on a common bench, and an upper bench supports the detectors thanks to two independent hexapods. The stiffness of the instrument is guaranteed thanks to a box architecture linking both benches. The volume of BATMAN is 1.4x1.2x0.75 m³, with a total mass of 400kg. Mounting of all sub-systems has been done and integration of the individual arms is under way. BATMAN on the sky is of prime importance for characterizing the actual performance of this new family of MOS instruments, as well as investigating the new operational procedures on astronomical objects (combining MOS and IFU modes, different spatial and spectral resolutions in the same FOV, absolute (spectro-) photometry by combining imaging and spectroscopy in the same instrument, automatic detection of transients …). This instrument will be placed at TNG by beginning-2019.

The quality of SiFAP (Silicon Fast Astronomical Photometer) at the TNG has already shown its ability to easily detect optical pulses from transitional millisecond pulsars and from other slower neutron stars. Up to now the photometer based on Silicon Photo Multipliers manufactured by Hamamatsu Photonics (MPPC, Multi Pixel Photon Counter) was mounted (on and manually aligned with) a MOS mask at the F/11 focal plane of the telescope. In order to have a more versatile instrument with the possibility to remotely center and point several targets during the night we have decided to build a new mechanical support for the MPPCs and mount it on the Namsyth Interface (NI), where originally OIG and later GIANO were hosted. The MPPC module devoted to observe the target will be placed at the center of the FoV (on-axis), while the reference signal will be collected from a peripheral star in the FoV (Field of view) by means of the MPPC module that will be set at this position by a combination of a linear stage movement and a derotator angle. At the same time we have introduced the option for a polarimetric mode, with a 3rd MPPC module and a polarizing cube beam-splitter that separates the states between this and the on axis MPPC. SiFAP has been developed with 3 independent custom electronic chains for data acquisition, exploiting the 3 different outputs (analog, digital, USB pre-processed) provided by the MPPCs modules. The electronic chain fed by the analog output is able to tag a single photon ToA (Time of Arrival) with a time resolution of 25 ns, while the remaining electronic chains can integrate the signal into time bins from 100 ms down to 20 μs. The absolute time is provided by a GPS unit with a time resolution of 25 ns at 50% of the rising edge of the 1PPS (1 Pulse Per Second) signal which is linked to the UTC (Universal Time Coordinated). Apart from the versatility with the remotely controlled on sky configuration of the MPPCs, the mounting of SiFAP2 at the NI allows for a permanent hosting of the instrument, readily available for observations. The new polarimetric mode will then offer other scientific opportunities that have not been explored so far in high-temporal resolution astronomy.

SPIRou is a near-IR (0.98-2.35μm) echelle spectropolarimeter / high precision velocimeter installed at the beginning of the year 2018 on the 3.6m Canada-France-Hawaii Telescope (CFHT) on Mauna Kea, Hawaii, with the main goal of detecting Earth-like planets around low mass stars and magnetic fields of forming stars. In this paper, the fiber links which connects the polarimeter unit to the cryogenic spectrograph unit (35 meter apart) are described. The pupil slicer which forms a slit compatible with the spectrograph entrance specifications is also discussed in this paper. Some challenging aspects are presented. In particular this paper will focus on the manufacturing of 35 meter fibers with a very low loss attenuation (< 13dB/km) in the non-usual fiber spectral domain from 0.98 μm to 2.35 μm. Other aspects as the scrambling performance of the fiber links to reach high accuracy radial velocity measurements (<1m/s) and the performances of the pupil slicer exposed at a cryogenic and vacuum environment will be discussed.

We report on commissioning the iodine absorption cell in the High Resolution Spectrograph (HRS) on the Southern African Large Telescope (SALT). The low-, medium- and high-resolution (LR, MR and HR) modes of this fibre-fed, dual-channel, white-pupil vacuum échelle spectrograph have been in use by the SALT consortium since 2014, but the high-stability (HS) mode requires exoplanet expertise not available in our community. The original commercial HRS iodine cell was unsuitable due to an excess of iodine so it was replaced with a suitable custom-built cell. This cell was characterised at high signal-to-noise, at a resolution of 106, using the Fourier Transform Spectrometer at the National Institute of Standards and Technology before incorporation into the HRS HS bench. A combination of calibration frames and on-sky data were then used to produce an HRS-specific version of an IDL software package that derives precision radial velocities (PRVs) from spectra taken through an iodine cell. Bright stars with highly stable RVs observed during a short engineering campaign in May 2018 demonstrate that SALT HRS is currently capable of delivering Doppler precision of 4-7m/s.

Ever more precise radial velocity instruments are needed to observe potential earth-like exoplanet targets that are beyond the range of current generation high resolution echelle spectrographs. Meanwhile, extreme adaptive optics systems at 8 meter class facilities have made ground based observations possible at the diffraction limit. In the field of Doppler spectroscopy, one way to take advantage of these AO capabilities is by the development of ultra-stable single mode fiber fed spectrographs.1 Coupling the light efficiently into SMFs with an extreme adaptive optics system offers significant advantage in removing modal noise, reducing instrument size, enabling superior environmental control and curbing cost. We report the design and challenges in building an ultra-stable spectrograph for the near infrared range. The design wavelength range is 650 to 1500 nm.

WINERED is a highly sensitive near-infrared (NIR) high-resolution spectrograph. The spectral coverage is 0.90 to 1.35μm (z, Y, J-bands) and the spectral resolutions are R = 28,000 (WIDE-mode, covering an entire WINERED’s wavelength region with a single exposure) and R = 70,000 (HIRES-modes, covering either Y- or J-band with a single exposure). Owing to the high-throughput optics (> 0.5) and the very low noise of the system, WINERED has the potential to detect the faintest objects when attached to 10 m class telescopes as reported in the previous SPIE meeting. In the beginning of 2017, WINERED was relocated from the 1.3 m Araki telescope in Koyama Astronomical Observatory, Japan, to the ESO 3.58 m New Technology Telescope (NTT) in La Silla Observatory, Chile, and began its scientific observations. By March of 2008, 30 nights in total were allocated for observation with the WINERED at the NTT. To further improve observational efficiencies at the NTT, we upgraded and refined several units of WINERED. New slits were installed to realize a medium spectral resolution and the better correction of the distorted echellogram, the grating holder for the mosaicked high-blazed echelle gratings were modified, the ghost problems observed on the HIRES-Y mode were fixed, and the I/F mechanical parts were fabricated for easy and highlyreplicable attachment to the NTT. After verifying a few performances critical for the sensitivity of the new telescope, the background ambient radiation at the NTT, which determines the limiting magnitude because WINERED is a warm instrument with no cold stop, is very similar (~0.1 photons sec^-1 pixel^-1 at 290 K and ~0.04 photons sec^-1 pixel¹ at 280 K) to those measured at Kyoto. The stability in wavelength, which could degrade the signal-to-noise ratios (SNRs) by artificial spiky-noises generated in the subtraction and correction of telluric emission/absorption lines, is measured to be less than 0.2 pixels during an observational run, although these can be further reduced by the crosscorrelation method which are applied for spectra taken at different timings during reduction. WINERED routinely provides spectra of the SNR > 500 for bright stars, and realized the detection of those of SNR = 30 for faint objects of J = 16.4 mag (for WIDE mode) and J=15.0 (for HIRES mode) with the exposure time of 8 hours using the narrowest slit at the NTT (even without AO).

The CEA CryoMechanism (CM35) was created in the late nineties from the association of basic industrial components. At this stage, the goal was to design a very robust and highly repeatable rotating actuator that could operate from room temperature, down to cryogenic temperatures (20K) with a very low power dissipation. This first model was designed according rules of thumb for ground instruments. Manufactured in 12 units series in 2004 (including two spare units), ten CM are operating once every hour in the mid-infrared imager/spectrometer VISIR, on the Very Large Telescope in Chile, without any major failure reported. From 2010 to 2012, within the framework of the Mid InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST), a significant evolution of the CM35 was done in order to become a space mechanism. The new CM35 was designed, manufactured and tested according to the flight qualification test program. For this test campaign, thermal cycles (293K-20K), vibrations and life-test (150,000 actuations) were carried out. This test phases allowed to highlight some upgrades to be implemented such as the vibrations behavior improvement. From 2008 to 2012, a smaller CM, called CM21, was developed with a major evolution in the mechanical architecture that reduced the number of part, so minimize the manufacturing cost and time to integration. This model was implanted in CAMISTIC instrument in Antarctic. Today, within the framework of EUCLID mission (launch expected by 2021), the CM35 development, based on the same basic industrial components from the beginning but with the optimized CM21 design, is complete and reaches the status of a flight model mechanism. This is one of the first flight components delivered in the Euclid space mission. The story of CM is not finished yet as this actuator is going to be dispatched into the ELT-METIS instrument by 2021 (Extremely Large Telescope, Mid Infrared ELT Imager and Spectrograph) to rotate around 20 optical wheels. To achieve this goal, the CM design has been reconsidered with a goal of cost optimization. This paper explains the system constraints that had an impact on the conception of the CryoMechanism keeping in mind the links with the cryogenic environment constraints. A focus is done on the mechanical simulations developed for the modeling of the bearing and the correlation from dynamic analysis and vibration test measures. The paper will highlight the manufacturing challenges that have led to a highly repeatable actuator, capable of operations in the range from 300K down to 10K.

The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development for the W.M. Keck Observatory. The instrument recently passed its preliminary design review and is currently in the detailed design phase. KPF is designed to characterize exoplanets using Doppler spectroscopy with a single measurement precision of 0.5 m s⁻¹ or better; however, its resolution and stability will enable a wide variety of other astrophysical pursuits. KPF will have a 200 mm collimated beam diameter and a resolving power greater than 80,000. The design includes a green channel (445 nm to 600 nm) and red channel (600 nm to 870 nm). A novel design aspect of KPF is the use of a Zerodur optical bench, and Zerodur optics with integral mounts, to provide stability against thermal expansion and contraction effects.

High-resolution spectroscopy is a key element for present and future astronomical instrumentation. In particular, coupled to high contrast imagers and coronagraphs, high spectral resolution enables higher contrast and has been identified as a very powerful combination to characterise exoplanets, starting from giant planets now, up to Earth-like planet eventually for the future instruments. In this context, we propose the implementation of an innovative echelle spectrometer based on the use of VIPA (Virtually Imaged Phased Array, Shirasaki 1996). The VIPA itself is a particular kind of Fabry-P´erot interferometer, used as an angular disperser with much greater dispersive power than common diffraction grating. The VIPA is an efficient, small component (3 cm × 2.4 cm), that takes the very advantage of single mode injection in a versatile design. The overall instrument presented here is a proof-of-concept of a compact, high-resolution (R > 80 000) spectrometer, dedicated to the H and K bands, in the context of the project “High-Dispersion Coronograhy“ developed at IPAG. The optical bench has a foot-print of 40 cm × 26 cm ; it is fed by two Single-Mode Fibers (SMF), one dedicated to the companion, and one to the star and/or to a calibration channel, and is cooled down to 80 K. This communication first presents the scientific and instrumental context of the project, and the principal merit of single-mode operations in high-resolution spectrometry. After recalling the physical structure of the VIPA and its implementation in an echelle-spectrometer design, it then details the optical design of the spectrometer. In conclusion, further steps (integration, calibration, coupling with adaptive optics) and possible optimization are briefly presented.

The InfraRed Doppler (IRD) instrument is a high-dispersion spectrograph that is available on Subaru Telescope to explore extrasolar planets via infrared radial velocity (RV) observations. The Subaru/IRD is especially useful in the search of a low-mass planet around cool M-type dwarfs for which infrared RV observations are essential. We report our early performance tests for IRD. IRD’s two H2RG detectors have been evaluated with our detector readout technique, ensuring that their readout noise is made sufficiently smaller than the stellar photon noise expected in our planned survey. We have also tested the instrumental stability of RV measurements from the laboratory data obtained with the IRD’s calibration systems including a laser frequency comb (LFC). Among our tested three types of velocity stability, the stability of comb spectra obtained with a multi-mode fiber (MMF) relative to that with another MMF is measured to be ∼1 m s⁻¹. We also infer from these tests that stellar RV measurements with an MMF can be calibrated with a short-term stability of 2 m s⁻¹ or better by the simultaneously-observed reference spectra of LFC. Furthermore, we report preliminary on-sky RV measurements calibrated with a Thorium-Argon hollow-cathode lamp for RV-stable stars (τ Ceti and Barnard's star) and a planet-host (51 Pegasi). These preliminary RV measurements help the further performance test of IRD that will be performed by the on-sky observations with LFC.

SPIRou is an innovative near infra-red echelle spectropolarimeter and a high-precision velocimeter for the 3.6 m Canada-France-Hawaii Telescope (CFHT – Mauna Kea, Hawaii). This new generation instrument aims at detecting planetary worlds and Earth-like planets of nearby red dwarfs, in habitable zone, and studying the role of the stellar magnetic field during the process of low-mass stars / planets formation. The cryogenic spectrograph unit, cooled down at 80 K, is a fiber fed double-pass cross dispersed echelle spectrograph which works in the 0.98-2.40 μm wavelength range, allowing the coverage of the YJHK bands in a single exposure. Among the key parameters, a long-term thermal stability better than 2 mK, a relative radial velocity better than 1 m.s ^-1 and a spectral resolution of 70K are required. After ~ 1 year of assembly, integration and tests at IRAP/OMP (Toulouse, France) during 2016/2017, SPIRou was then shipped to Hawaii and completely re-integrated at CFHT during February 2018. A full instrument first light was performed on 24th of April 2018. The technical commissioning / science validation phase is in progress until June 2018, before opening to the science community. In this paper, we describe the work performed on integration and test of the opto-mechanical assemblies composing the spectrograph unit, firstly in-lab, in Toulouse and then on site, at CFHT. A review of the performances obtained in-lab (in 2017) and during the first on-sky results (in 2018) is also presented.

SPIRou is a new near-infrared echelle spectropolarimeter and high precision radial velocity instrument, implemented at the 3.6m Canada-France Hawaii Telescope (CFHT, Mauna Kea) in early 2018. It aims at detecting and characterizing Earth-like planets around M dwarfs and studying stellar and planetary formation in the presence of stellar magnetic field. The calibration unit, with its radial-velocity reference module, is essential to the short- and long-term precision at the level of 1 m/s. We describe the final calibration unit that has been installed. We give technical results such as thermal background level, lamps flux level, lamps stability, and report some technical issues with their solution.

The NIR echelle spectrograph GIANO-B at the Telescopio Nazionale Galileo is equipped with a fully automated online DRS: part of this pipeline is the GOFIO reduction software, that processes all the observed data, from the calibrations to the nodding or stare images. GOFIO reduction process includes bad pixel and cosmic removal, flat-field and blaze correction, optimal extraction, wavelength calibration, nodding or stare group processing. An offline version of GOFIO will allow the users to adapt the reduction to their needs, and to compute the radial velocity using telluric lines as a reference system. GIANO-B may be used simultaneously with HARPS-N in the GIARPS observing mode to obtain high-resolution spectra in a wide wavelength range (383-2450 nm) with a single acquisition. In this framework, GOFIO, as part of the online DRS, provides fast and reliable data reduction during the night, in order to compare the infrared and visible observations on the fly.

The NEID spectrometer is an optical (380-930 nm), fiber-fed, precision Doppler spectrometer currently in de- velopment for the WIYN 3.5 m telescope at Kitt Peak National Observatory as part of the NN-EXPLORE partnership. Designed to achieve a radial velocity precision of < 30 cm/s, NEID will be sensitive enough to detect terrestrial-mass exoplanets around low-mass stars. Light from the target stars is focused by the telescope to a bent Cassegrain port at the edge of the primary mirror mechanical support. The specialized NEID “Port Adapter” system is mounted at this bent Cassegrain port and is responsible for delivering the incident light from the telescope to the NEID fibers. In order to provide stable, high-quality images to the science instrument, the Port Adapter houses several sub-components designed to acquire the target stars, correct for atmospheric dis- persion, stabilize the light onto the science fibers, and calibrate the spectrometer by injecting known wavelength sources such as a laser frequency comb. Here we provide an overview of the overall opto-mechanical design and system requirements of the Port Adapter. We also describe the development of system error budgets and test plans to meet those requirements.

SPIRou (SpectroPolarimètre Infra-Rouge in French), is a near-infrared, fiber-fed spectropolarimeter at the CanadaFrance-Hawaii Telescope (CFHT) which gives full spectral coverage from 0.98 to 2.35 μm with a resolving power of 70,000. The main science drivers for SPIRou are (i) detecting and characterizing exoplanets around nearby M dwarfs through high-precision (1 m/s) velocimetry, and (ii) investigating the impact of magnetic fields on star/planet formation through spectropolarimetry. One of the requirements for achieving this challenging radial velocity (RV) precision is ensuring that the observed star does not move with respect to the instrument entrance aperture by more than 0.05 arcseconds RMS over the course of the observation. This is complicated by the fact that the guiding uses light from the science target so that only about 13% of the light (10% from the wings and 3% from the core) is available in seeing conditions of 0.65 arc-seconds in H band. To achieve this level of guiding accuracy, a fast guiding system has been implemented in the injection module of the instrument. This paper describes the system, its performance in tests on the sky with the CFHT since the delivery of SPIRou in January 2018, and gives comparisons to laboratory measurements and simulations.

The Gemini High-Resolution Optical SpecTrograph (GHOST) is the newest instrument being developed for the Gemini telescopes, in a collaboration between the Australian Astronomical Observatory (AAO), the Herzberg Institute for Astrophysics, National Research Council (HIA-NRC) in Canada, and the Australian National University. This paper describes the design of the fiber optic system, developed by AAO. This system links the GHOST multi-object positioner, mounted on Gemini's Cassegrain focus, with the HIA-NRC developed spectrograph, located in the pier lab, 20 meters below the main observatory floor. The GHOST optical cable consists of 62 fibers, Polymicro FBP53/74/94P (53 μm core, 94 μm polyimide buffer), packed into 8 furcation tubes. The optical fibers are held inside the furcation tubes by friction, with between one and twelve fibers in each of the individual tubes. The furcation tubes are mechanically secured to manifold and anchor assemblies by bonding to integral Kevlar yarn within the tubing. The cable includes an interlock switch, linked to the telescope control system, to halt all telescope motions if the cable becomes overstressed. Fibers are terminated by two integral field units (IFU1 and IFU2), guiding and science slits and a calibration light entry port. Mode scrambling is achieved by mechanical agitation in two orthogonal directions, with adjustable frequency and amplitude of up to 10 Hz and 50 mm, respectively.

Precision Doppler spectroscopy serves as an important tool for Radial Velocity (RV) observations of stars. High precision spectroscopy is bound by two major challenges, first being the instrument instability which is mainly caused by temperature and pressure variations and second, the limitations imposed by traditional wavelength calibration methods. In this work we report our progress on the development of a passively stabilized Fabry-Perot (FP) calibrator. We have designed and built an air-spaced etalon with 30 GHz free spectral range for accurately tracking the short-term drift of our high resolution (R = 60,000) Echelle spectrograph on Himalayan Chandra Telescope (HCT), Hanle. Instrument is built using off-the-shelf components, with the required temperature and pressure stability being achieved in initial test runs. For transporting light in and out of the vacuum system without incurring losses at fiber interconnects, we have used a simple way to insert a FC/APC connectorized fiber into the flange. We also present the results of transmission spectra of the FP taken with high resolution Fourier Transform Spectrometer.

The third version of the High Accuracy Radial velocity Planet Searcher (HARPS3) instrument is built for a ten-year programme aimed at achieving 10 cm/sec radial velocity precision on nearby stars to search for Earth-like planets. HARPS3 will be commissioned on the to-be-roboticized 2.54-m Isaac Newton Telescope at La Palma in 2021. One of the main changes compared to its predecessors is the novel dual-beam Cassegrain focus, featuring a stabilised beam feed into the HARPS3 spectrograph and an insertable polarimetric sub-unit. This polarimetric sub-unit enables HARPS3 to directly measure stellar activity signatures, which can be useful for correcting activity-induced radial velocity jitter in the search for Earth-like planets. The sub-unit consists of superachromatic polymer quarter- and half-wave retarders for circular and linear polarizations respectively, designed to suppress polarized fringing, and a novel polarimetric beam splitter based on a wire-grid design, separating the two polarimetric beams by 30 mm and feeding two separate science fibers. The dual-beam exchange implementation in combination with the extreme stability of the HARPS3 spectrograph enables a polarimetric sensitivity of 10⁻⁵ on bright stars. One of the main challenges of such a system is in the characterization of instrumental polarization effects which limit the polarimetric accuracy of the polarimetric observing mode. By design and characterization of this subsystem and by pre-emptively mitigating possible noise sources, we can minimize the noise characteristics of the polarization sub-unit to allow for precise observations. In this paper we report on the design, realization, assembly, alignment, and testing of the polarimetric unit to be installed in the Cassegrain Adaptor Unit of the HARPS3 spectrograph

Las Cumbres Observatory Global Telescope Network (LCOGT) has built the Network of Robotic Echelle Spectrographs (NRES), consisting of four identical, high-resolution optical spectrographs, each fiber-fed simultaneously by up to two 1-meter telescopes and a calibration source. Two units have been installed and are currently executing scientific observations. A third unit has been installed and is presently in commissioning. A fourth unit has been shipped to site and will be installed in mid 2018. Operating on four separate continents in both the Northern and Southern hemispheres, these instruments comprise a globally-distributed, autonomous spectrograph facility for stellar classification and high-precision radial velocity of bright stars. Simulations suggest we will achieve long-term radial velocity precision of 3 m/s in less than an hour for stars with V < 12. Radial velocity precision of 75 m/s has already been demonstrated with our automatic data-processing pipeline across multiple sites. Work is ongoing to improve several NRES system components including telescope control (robotic source acquisition in particular) and the data-processing pipeline. In this document we briefly overview the NRES design, its purpose and goals, results achieved to date in the field, and the ongoing development effort to improve instrument performance.

MAROON-X is a red-optical, high precision radial velocity spectrograph currently nearing completion and undergoing extensive performance testing at the University of Chicago. The instrument is scheduled to be installed at Gemini North in the first quarter of 2019. MAROON-X will be the only RV spectrograph on a large telescope with full access by the entire US community. In these proceedings we discuss the latest addition of the red wavelength arm and the two science grade detector systems, as well as the design and construction of the telescope front end. We also present results from ongoing RV stability tests in the lab. First results indicate that MAROON-X can be calibrated at the sub-m s⁻¹ level, and perhaps even much better than that using a simultaneous reference approach.

VELOCE is an IFU fibre feed and spectrograph for the AAT that is replacing CYCLOPS2. It is being constructed by the AAO and ANU. In this paper we discuss the design and engineering of the IFU/fibre feed components of the cable. We discuss the mode scrambling gain obtained with octagonal core fibres and how these octagonal core fibres should be spliced to regular circular core fibres to ensure maximum throughput for the cable using specialised splicing techniques. In addition we also describe a new approach to manufacturing a precision 1D/2D array of optical fibres for some applications in IFU manufacture and slit manufacture using 3D printed fused silica substrates, allowing for a cheap substitute to expensive lithographic etching in silicon at the expense of positional accuracy. We also discuss the Menlo Systems laser comb which employs endlessly-singlemode fibre to eliminate modal noise associated with multimode fibre transmission to provide the VELOCE spectrograph with a stable and repeatable source of wavelength calibration lines.

We present the design and test results of a double-scrambler and fiber agitator system for the Keck Planet Finder (KPF) spectrograph. The mechanical agitator for modal noise suppression is constructed from two linear stages with the fibers mounted in a “W” curve. When driven back-and-forth at different rates, the stages change the position of the fiber curves, and hence vary the modes propagating through the fiber. Near-field temporal centroid shifts caused by modal-noise are reduced by a factor of 100 by the agitator, while mid-range spatial frequencies have reduced power by a factor of ∼300 in the near-field, and ∼1000 in the far-field. The scrambling system incorporates two octagonal fibers, and a scrambler consisting of two identical cemented lenses ∼20 cm apart, which exchanges the optical near- and far-fields of the fibers. The scrambler shows scrambling gains >16,000 in the near-field, and >40,000 in the far-field. The measured throughput efficiency of 99.3% of the expected maximum demonstrates that scrambler-induced focal ratio degradation (FRD) is minimal. The scrambler also serves as the feed-through into the vacuum chamber where the spectrograph is housed, thereby removing concerns about stressing the fibers, and introducing FRD, at this interface. Our illumination stabilization system, consisting of two octagonal fibers, a two lens scrambler, and a mechanical agitator, produces very homogeneous fiber output in both the near and far-fields. When coupled to the Keck Planet Finder spectrograph, this system provides illumination stability corresponding to a velocity of 0.30 m s⁻¹ .

We present here the optical and mechanical design of a fiber-fed High-resolution spectrograph at resolution (R) = 100,000 which will be under vacuum (0.001 to 0.005 mbar) and temperature controlled environment at 25C ± 0.001C. The spectrograph will be attached to our upcoming new PRL 2.5m aperture telescope at Gurushikar, Mount Abu, Rajasthan, India. The spectrograph is named PARAS-2 after the successful operation of PARAS (PARAS-1) with our existing 1.2m aperture telescope at Gurushikar, Mount Abu since 2012 summer. The spectrograph (PARAS-2) will be operating in the range of 380nm to 690nm wavelength in a single shot using Grism as a Cross Disperser, R4 Echelle at blaze angle of 76degrees, and pupil diameter of 200 mm. We will use a combination of octagonal and circular fibers along with double scrambler and simultaneous calibration for getting down to the RV precision of 50cm/s or better (< 50cm/s). Minimum 30% time will be reserved for exoplanet work with the spectrograph on the 2.5m telescope when it becomes operational in early 2020. The overall efficiency of the whole spectrograph (Echelle, M1, M2, FM, Grism, Camera lens system, Dewar window) excluding fiber is expected to be 22.5% - 28% and 4% - 8% including optical fiber, telescope and fibertelescope interface losses.

GHOST is a high resolution spectrograph system currently being built for the Gemini South Observatory in Chile. In the Cassegrain unit, the observational targets are acquired on integral field units and guided during science exposures, feeding the fiber cable to the temperature-stabilized echelle spectrograph. The Cassegrain unit is mounted on the Gemini telescope, and consists of a main structural plate, the two object positioners and ballast frame. The image from each of the two science beams passes through a field lens and a mini-atmospheric dispersion corrector and is then captured by the integral field unit. The positioner moves each corrector-integral field unit assembly across the focal surface of the telescope. The main structural plate provides the interface for the positioner and ballast frame to the telescope structure. In this paper we describe the final design and assembly of the GHOST Cassegrain unit and report on the outcome of on-sky testing at the telescope in Chile.

High precision Doppler observations of bright stars can be made efficiently with small aperture telescopes. We are constructing a high resolution echelle spectrograph for the new 0.6 m telescope at Central Washington University. The spectrograph is fed by a multimode fiber and operates in the visible wavelength range of 380-670 nm. The spectrograph uses a white pupil design with 100 mm beam diameter and a monolithic R4 echelle grating.

Veloce is an ultra-stabilized Echelle spectrograph for precision radial velocity measurements of stars. In order to maximize the grating performance, the air temperature as well as the air pressure surrounding it must be maintained within tight tolerances. The control goal was set at +/-10 mK and +/-1 mbar for air temperature and pressure respectively. The strategy developed by the design team resulted in separate approaches for each of the two requirements. A constrained budget early in the concept phase quickly ruled out building a large vacuum vessel to achieve stable air pressure. Instead, a simplified approach making use of a slightly over pressurized enclosure containing the whole spectrograph was selected in conjunction with a commercially available pressure controller. The temperature stability of Veloce is maintained through a custom array of PID controlled heaters placed on the outer skin of the internal spectrograph enclosure. This enclosure is also fully lined with 19 mm thick insulating panels to minimize the thermal fluctuations. A second insulated enclosure, built around the internal one, adds a layer of conditioned air to further shield Veloce from the ambient thermal changes. Early success of the environment control system has already been demonstrated in the integration laboratory, achieving results that amply exceed the goals set forth. Results presented show the long term stability of operation under varying barometric conditions. This paper details the various challenges encountered during the implementation of the stated designs, with an emphasis on the control strategy and the mechanical constraints to implement the solutions.

Hanle echelle spectrograph (HESP) is a high resolution, bench mounted, fiber-fed spectrograph at visible wavelengths. The instrument was recently installed at the 2m Himalayan Chandra Telescope (HCT), located at Indian Astronomical Observatory (IAO), Hanle at an altitude of 4500m. The telescope and the spectrograph are operated remotely from Bangalore,(∼ 3200km from Hanle), through a dedicated satellite link. HESP was designed and built by Kiwi Star Optics, Callaghan Innovation, New Zealand. The spectrograph has two spectral resolution modes (R=30000 and 60000). The low resolution mode uses a 100 micron fiber as a input slit and the high resolution mode is achieved using an image slicer. An R2 echelle grating, along with two cross dispersing prisms provide a continuous wavelength coverage between 350-1000nm. The spectrograph is enclosed in a thermally controlled environment and provides a stability of 200m/s during a night. A simultaneous thorium-argon calibration provides a radial velocity precision of 20m/s. Here, we present a design overview, performance and commissioning of the spectrograph.

GREGOR at night spectrograph (GANS) is a high-resolution thermally-stabilised vacuum-enclosed fixed-format fiber-fed Echelle spectrograph. GANS will be installed starting 2018 alongside the daytime instrumentation in the building of the 1,5m Gregor Solar Telescope at the Observatorio del Teide at Izan˜a, Tenerife. Specified resolving power is R~55k with wavelength coverage from 470 to 680 nm in single shot on 2k 2k CCD with 3”, 50μm fiber on sky, and with space between orders for simultaneous calibration light in the form of a Fabry-Perot Etalon or a Laser-comb spectrum. The end-to-end simulated radial velocity precision performance estimate is 2 ms⁻¹. The main observing project of GANS will be the ground-based follow-up survey of TESS and PLATO2.0 exoplanet candidates. GANS will observe its targets in autonomous operation without human intervention using the normally human-operated day-time observatory. Limited operations will begin in first half of 2019 with first science-light planned for summer 2019.

The NEID Port Adapter is the interface between the WIYN 3.5m Telescope and the NEID fiber-fed spectrometer. The spectrometer requires the stellar jitter to be controlled for 90% of the time to within 50 milli-arc seconds for visual magnitudes 12, and 200 milli-arc seconds for V-magnitudes 12-16. The NEID Port Adapter will use an Andor EMCCD with 13 micron pixels, and a tip/tilt piezo stage from nPoint with a lowest resonant mode of 479 Hz. We expect to meet the requirement with a closed-loop rate of 27 Hz. We have data taken at the WIYN telescope consisting of stellar centroids captured at a rate of 108.75 Hz, which we rebin to test the response at lower sampling rates. We present the results of feeding these waveforms into the nPoint controller and measuring the actual response.

Observations of nearby terrestrial exoplanets atmospheres may reveal if those planets show evidence of bioactivity. Molecular oxygen, along with methane, has been identified as the leading biomarkers in the Earth atmosphere [1]. Our capability to detect O₂ in planets outside of our solar system is limited even when considering the next generation of Extremely Large Telescopes (ELTs). Due to refraction effects in an exoplanet atmosphere, transmission spectroscopy, the preferred detection technique, does not probe the high pressure layers of the atmosphere close to the exoplanet surface [2,3]. Hence, the observed O2 transition lines in an exoplanet atmosphere are narrower than the equivalent telluric lines observed in the Earth atmosphere, and are partially unresolved even when observing at ℛ ≈ λ/δλ ~10⁵), typical of modern high resolution spectrographs. The transition lines become fully resolved at ℛ~3 − 5 ∙ 10⁵), at which detection becomes favorable [4,5]. Most modern high resolution spectrographs are echelle spectrographs. These instruments utilize echelle gratings with low line densities blazed for high diffraction orders. For echelle spectrographs on ELTs at seeing limited conditions, the collimator and echelle grating dimensions needed to achieve spectral resolutions in excess of ℛ~10⁵) become impractical. While several techniques can increase the resolution obtained by an echelle spectrograph, none of them seems to offer the desired resolution increase for seeing limited observations at visible wavelengths [6,7]. We conclude that a novel approach for extremely high resolution spectroscopy with ELTs is in order. In this paper, we propose a concept instrument capable of extreme high resolutions on ELTs under seeing limited condition. The instrument is based on the interference properties of Fabry Perot Interferometers (FPIs). A single FPI of modest dimensions can achieve a resolving power well in excess of ℛ~10). In contrast to the high spectral resolving power, the sampling frequency of an FPI tends to be quite low in most practical cases. In addition, the interference orders of the FPI will overlap. Hence, a single etalon can not generate a continuous spectrum. We circumvent these problems by chaining several FPIs, each one with a slightly different thickness. The beam reflected from each FPI is feeding the next FPI in the chain, while the beam transmitted by each FPI is imaged onto the slit of an external spectrograph capable of separating interference orders. The thickness difference between FPIs in the chain dictates the instrument target resolution, while the absolute thickness of the FPIs in the chain dictates the resolution required from the external spectrograph to separate the overlapping interference orders. We begin our discussion with an analysis of an ideal FPI array instrument. We than present a practical design and discuss its expected performance when taking into account manufacturing and alignment errors. We conclude with a summary and future plans. Throughout the paper, we focus our discussion on the O2 A-band (λ~755 − 775nm), the favorable detection waveband for O2 using the transmission spectroscopy technique [4]. In addition, we assume the FPIs are fused silica etalons1. A detailed analysis of an FPI instrument in the context of molecular oxygen detection can be found in [5].

ESPRESSO (Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations) is a fiber-fed, crossdispersed, high resolution and ultra-stable echelle spectrograph is designed to enable a new quality of quantitative science on ESO’s Very Large Telescope (VLT). Its science cases, range from exo-planets to the study of the physical constants call for a precision of 10 cm/s in radial velocity. To this end the ESPRESSO spectrograph, recently installed at ESO’s Paranal observatory, uses a laser frequency comb (LFC) to provide a grid of equidistant lines to deliver a high precision, high accuracy wavelength calibration traceable to the SI frequency standard. The unit is inserted in the light path between the laser frequency comb and the calibration unit delivering the calibration light to the ESPRESSO spectrograph. The scrambler ensures that the injection fibre of the spectrograph is homogenously illuminated preserving the excellent qualities of the LFC light and thus avoiding introducing systematics that could compromise the wavelength calibration and the science performance. In this context it is essential that photon-noise limited performance is achieved. The ESPRESSO spectrograph will be available to the astronomical community starting October 1st, 2018.

The Habitable-zone Planet Finder (HPF) is a highly stabilized fiber fed precision radial velocity (RV) spec- trograph working in the Near Infrared (NIR): 810 – 1280 nm. In this paper we present an overview of the preparation of the optical fibers for HPF. The entire fiber train from the telescope focus down to the cryostat is detailed. We also discuss the fiber polishing, splicing and its integration into the instrument using a fused silica puck. HPF was designed to be able to operate in two modes, High Resolution (HR- the only mode mode currently commissioned) and High Efficiency (HE). We discuss these fiber heads and the procedure we adopted to attach the slit on to the HR fibers.

Single-mode fiber (SMF) spectrographs fed with adaptive optics (AO) offer a unique path for achieving extremely precise radial velocity (EPRV) measurements. We present a radial velocity (RV) error budget based on end-to-end numerical simulations of an instrument named iLocater that is being developed for the Large Binocular Telescope (LBT). Representing the first AO-fed, SMF spectrograph, iLocater’s design is used to quantify and assess the relative advantages and drawbacks of precise Doppler time series measurements made at the diffraction limit. This framework can be applied for trade-study work to investigate the impact of instrument design decisions on systematic uncertainties encountered in the regime of sub-meter-per-second precision. We find that working at the diffraction-limit through the use of AO and SMF’s allows for high spectral resolution and improved instrument stability at the expense of limiting magnitude and longer integration times. Large telescopes equipped with AO alleviates the primary challenges of SMF spectrographs.

In this paper the authors present a concept, design, implementation and results of a vacuum and cryogenic system for the ESPRESSO VLT instrument. The system is comprised of two major control functionalities: vacuum and cryogenics. The Vacuum system is a shared manifold for five chambers, and includes a pre-pump and a turbo molecular pump as vacuum sources. The Cryogenic System is based on a continuous circulation of Liquid Nitrogen (LN2). One shared LN2 line is used for supply and control of the cool down of two detector cryostats and two sorption pumps (also called cryopumps). The Cryopumps are a passive vacuum pumps to compensate for the outgassing of the big vacuum chamber (volume approx.10 m³ ), minimizing vibrations during operation. The control of the Vacuum System is PLC-based, whereas the Cryogenic is PPC (Program and Process Control) and Lakeshore 336 based. There is special emphasis on the temperature stability of the detector cryostat (goal <10 mK RMS). Result data for the operation shown are from ESPRESSO commissioning in late 2017.

The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development for the W.M. Keck Observatory. To measure Doppler shifts to 0.5 m/s or better requires some of the optics be stable to 2 nm vertically and 2 nrad in pitch angle throughout a potentially one hour long observation. One traditional approach to this thermal stability problem is to build a metal bench and then control the spectrometer thermal environment to milli-Kelvin levels. An alternative approach used by KPF is to employ a Zerodur bench of extremely low coefficient of expansion (CTE), which relaxes the thermal stability required for the spectrometer assembly. Furthermore, Zerodur optics with integral mounts are used where possible, and are placed in contact with the bench through Zerodur shims. Springs are used to preload the optics and shims within pockets machined into the Zerodur bench. We will describe how this approach has been adapted for each optic (some of which are 450 mm high with a mass of 30 kg), and how the system meets our earthquake survival requirement of 0.92 g. This mounting scheme allows us to avoid using high-CTE metals or adhesives within the optic mounting system, and therefore fully exploit the high thermal stability of the Zerodur optical bench.

NEID is a new extreme precision Doppler spectrometer for the WIYN telescope. It is fiber fed and employs a classical white pupil Echelle configuration. NEID has a fiber aperture of only 0.92” on sky in high-resolution mode, and its tight radial velocity error budget resulted in very stringent stability requirements for the input illumination of the spectrograph optics. Consequently, the demands on the fiber injection are challenging. In this paper, we describe the layout and optical design of the injection module, including a broadband, high image quality relay and a high-performance atmospheric dispersion corrector (ADC) across the bandwidth of 380 – 930 nm.

Precise wavelength calibration is a persistent problem for highest precision Doppler spectroscopy. The ideal calibrator provides an extremely stable spectrum of equidistant, narrow lines over a wide bandwidth, is reliable over timescales of years, and is simple to operate. Unlike traditional hollow cathode lamps, etalons provide an engineered spectrum with adjustable line distance and width and can cover a very broad spectral bandwidth. We have shown that laser locked etalons provide the necessary stability with an ideal spectral format for calibrating precision Echelle spectrographs, in a cost-effective and robust package. Anchoring the etalon spectrum to a very precisely known hyperfine transition of rubidium delivers cm/s-level stability over timescales of years. We have engineered a fieldable system which is currently being constructed as calibrator for the MAROON-X, HERMES, KPF, FIES and iLocater spectrographs.

Pierced mirrors are used in high resolution and ultrastable spectrographs to feed guiding cameras and to improve the target stability. This paper describes the concept, design, manufacture, test and integration of ESPRESSO pierced mirrors which are part of the Fiber Link subsystem. ESPRESSO is a spectrograph located in the Coude Laboratory of VLT that can be feed by the light of any VLT telescope. Similar mirrors will be used in the Fiber Link subsystem of NIRSP spectrograph which is an Infrared spectrograph for the 3.6 m telescope of the Silla Observatory.

GIANO is the IR high resolution spectrograph of the TNG. It covers the 950-2450 nm wavelengths range in a single shot at a resolving power of R=50,000. This document describes the first fundamental steps of the data reduction, namely eliminating the curvature of the traces and the tilt of the slit images. These effects can be accurately modeled and corrected using a physical model of the instrument. We find that the curvature and tilt parameters did not vary during the whole lifetime of the instrument. In particular, they were not affected by thermal cycles or by the works performed to mount the spectrometer on its new interface. A similar ab-initio modeling is also applied to the wavelength calibration that can be accurately (0.03 pixel r.m.s.) defined using a minimum number of parameters to fit. This approach is particularly useful when using a calibration source with an irregular wavelengths coverage; e.g. for the U-Ne lamp that has only few lines in the 2000 nm - 2300 nm wavelengths range.

Precision in the Radial Velocity (RV) measurements depends upon the efficiency of the technique to remove instrumental artifacts from stellar measurements. Iodine absorption cell technique is being implemented for high precision studies with the Echelle spectrograph operating at Vainu Bappu Telescope (VBT), Kavalur, India. Since the star spectrum is convolved with the PSF of the spectrograph, the asymmetries in the PSF are imposed on the stellar spectral lines. The fiber fed Echelle spectrograph is a general purpose instrument, designed for high resolution (R = 60,000) spectroscopic observations. The asymmetries in the Point Spread Function (PSF) arise due to the off-axis launching of the stellar beam into the collimator and vignetting across the field. Apart from this, due to usage constraints, the grating of the spectrograph is a movable component. The impact on the Doppler shift calculations due to the movable components in the spectrograph is to be estimated. For upgrading the spectrograph for precision studies, the component level sensitivity for RV is to be analyzed. Thus, instrument design asymmetries and component induced PSF variations are analyzed to estimate the limitations of the spectrograph for precision studies. We have developed Zemax based optical design of the spectrograph to estimate the PSF variations and design limitations on the RV studies. Here, we present a model developed in Zemax and a preliminary analysis on RV sensitivity and the PSF asymmetries of the spectrograph. These instrument variations are to be taken as input during RV data reduction for precision measurements.

The wavelength calibration and nightly drift measurements for CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs) are provided by a combination of hollow cathode lamps and two Fabry-Pérot units. CARMENES consists of two spectrograph, one for the visible part of the spectrum (520 -960 nm) and one for the near infrared (960 - 1710 nm). Each spectrograph has its own calibration unit and its own Fabry-Pérot. The calibration units are equipped with Th-Ne, U-Ar and U-Ne hollow cathode lamps as well as a flat field lamp. The Fabry-Pérots are optimized for the wavelength ranges of the spectrographs and use halogen-tungsten lamps as light sources. The Fabry-Pérots have a free spectral range of 15 GHz for the visible and 12.2 GHz for the near infrared which translates to 17,900 useful emission lines for the visible spectrograph and 9,700 for the infrared. These lines are used to compute the wavelength solution, and to monitor the instrumental drift during the night. The Fabry-Pérot units are temperature and pressure stabilized and designed to reach an internal stability of better than 10 cm/s per night. Here, we present the designs of both Fabry-Pérot units and the calibration units.

The LAMOST telescope has been officially observed for the past seven years since 2009, and many parts of the telescope are currently being upgraded. The fiber positioning unit of the focal plane instrument is also planned to be upgraded again. In order to ensure a higher positioning accuracy of the fiber positioning unit, the newly developed fiber positioning system adopts a closed-loop camera to photograph the unit fiber position in real time, and feeds back to the control system to implement multiple positioning to improve the positioning accuracy. This article focuses on an improved optical center of gravity algorithm for optical fiber location based on the optical center of gravity algorithm. The factors affecting the position measurement of the optical fiber spot are optimized, and the recognition accuracy of the spot position under different conditions is improved.

With more than 200 scientists and engineers involved, the design and manufacture of the 4MOST instrument, a secondgeneration spectroscopic instrument built for ESO's 4.1-metre VISTA telescope, is a challenge requiring the implementation of an efficient quality assurance strategy during each project phase (i.e., design, manufacture, test, installation, and operation), and including the maintenance. This paper introduces the 4MOST product assurance approach used by the project to make sure that 4MOST will comply with all necessary quality and safety requirements over the whole instrument’s lifetime of 15 years. For quality assurance, the guiding principles are mainly given by the ISO 10007:2017 and ISO 9001:2015 quality management standards. Related to safety, 4MOST design and manufacture complies not only with the essential safety requirements from the European Union New Approach Directives (CE Marking Directives), but also with the additional requirements coming from the ESO Safety Policy, issued by the ESO Management for ESO-wide application. The implementation of the 4MOST project’s Quality Assurance and Configuration Management is described in detail in the paper.

The Australian Astronomical Observatory’s (AAO’s) AESOP project is part of the 4 metre Multi-Object Spectrograph Telescope (4MOST) system for the VISTA telescope. It includes the 2436-fiber positioner, space frame and electronics enclosures. The AESOP concept and the role of the AAO in the 4MOST project have been described in previous SPIE proceedings. Prototype tests, which were completed early in 2017 demonstrated that the instrument requirements are satisfied by the design. The project final design stage has recently been completed. In this paper, key features of the AESOP positioning system design, along with the techniques developed to overcome key mechanical, electronic, and software engineering challenges are described. The major performance requirement for AESOP is that all 2436 science fiber cores and 12 guide fiber bundles are to be re-positioned to an accuracy of 10 µm within 1 minute. With a fast prime-focus focal-ratio, a close tolerance on the axial position of the fiber tips must be held so efficiency does not suffer from de-focus losses. Positioning accuracy is controlled with the metrology cameras installed on the telescope, which measures the positions of the fiber tips to an accuracy of a few µm and allows iterative positioning until all fiber tips are within tolerance. Maintaining co-planarity of the fiber tips requires accurate control in the assembly of several components that contribute to such errors. Assembly jigs have been developed and proven adequate for this purpose. Attaining high reliability in an assembly with many small components of disparate materials bonded together, including piezo ceramics, carbon fiber reinforced plastic, hardened steel, and electrical circuit boards, has entailed careful selection and application of cements and tightly controlled soldering for electrical connections.

Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS) is a new multi-Integral Field Unit (IFU) instrument, planned to be mounted on the 3.6m Devasthal optical telescope in Nainital, India. It has eight identical, fiber-fed spectrographs to disperse light coming from 16 IFUs. The spectrographs produce 2,304 spectra over a 370-740nm wavelength range simultaneously with a spectral resolution of R=1200-2400. It is composed of all-refractive, allspherical optics designed to achieve on average 26.0% throughput from the telescope to the CCD with the help of high transmission spectrograph optics, volume phase holographic grating, and graded coated e2v 2K by 4K CCD. We present the optical and opto-mechanical design of the spectrograph as well as current development status. Optics and optomechanical components for the spectrographs are being fabricated.

4MOST (4-meter Multi-Object Spectroscopic Telescope) is a wide-field, fiber-feed, high-multiplex spectroscopic survey facility to be installed on the 4-meter ESO telescope VISTA in Chile. Its backend consists of one high resolution spectrograph and two identical low resolution spectrographs. The instrument is presently in the final design phase (review in May 2018) and is expected to enter full operations at the beginning of 2023 ([1] and [2]). The high resolution spectrograph (HRS) will afford simultaneous observations of up to 812 targets – over a hexagonal field of view of ~ 4.1 square degrees on sky – with a spectral resolution R>18,000 covering wavelength ranges between 393 and 679 nm in three channels. The optical design of the instrument is described in detail in [5]. In February 2017 the final design review for the optics was held and passed successfully. The final design review for the mechanics and all other parts of the instrument was held in May 2018. A summary and update of the optical and mechanical design of the HRS are presented in this paper. The detailed status of the manufacturing of the optics is given. The procedures and tools used during the AIT phase for the optical alignment of the HRS system, as well as the performance tests and characterizations are described.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We report progress on a predictive sky background model for DESI, built on the spectra from the 5-year Baryon Acoustic Oscillation Spectroscopic Survey (BOSS). This dataset consists of 1 million unique sky spectra covering 360 - 1040 nm collected in a variety of observational conditions. Using a fitted profile of the line spread function from the BOSS spectrograph, we separate the background continuum flux from the airglow lines, allowing us to study the behavior of both distinct emission sources across a large parameter space. Including both dark and bright sky conditions and covering the majority of the 24th solar cycle, our analysis provides new measurements of the inter-line sky continuum. The analysis of this paper is limited to the continuum flux in dark sky conditions at several wavelengths. This improved spectroscopic sky background model can be used in simulations and forecasting for DESI and other surveys.

We discuss the optical design of an infrared multi-object integral-field spectrograph (IRMOS) that is designed to take advantage of the multi-object adaptive optics corrected field at the Gemini telescope. The IRMOS is designed for the Gemini Telescope, so we call this instrument GIRMOS. The GIRMOS has four identical Integral-Field Spectrographs (IFSes), which employ a unique slicer design to arrange the integral field along a slit to obtain two-dimensional spectroscopy. Each IFS can pick off the individual fields of view of 1.0x1.0”, 2.1x2.1”, 4.2x4.2” over a 2’ diameter fieldof- regard, at the spatial sampling scales of 25mas, 50mas, and 100mas, respectively. Spectral resolutions of R~3000 and 8000 are available in J, H, and K-bands from 1.0 to 2.4μm. The primary design constraints are associated with diffractive effects from the grating and spectrograph camera.

Metrology Camera System (MCS) was designed to make a closed-loop control of the optical fiber position in Fiber Positioning System (FPS) on the focal plate of the LAMOST. The stability of the metrology platform is the key factor to the quality of camera shooting. A precise adjustable mechanism was designed in this paper to achieve the platform’s pitching and horizontal rotation adjustment. And also a vibration isolation system using Magnetic Negative Stiffness (MNS) and positive spring in parallel was designed to decrease the effect of vibration, which was caused by the multiple complex vibration loads existing in the working environment, on the platform. Furthermore, an air conditioning system using the semiconductor refrigerator and resistance heater was designed to ensure working temperature of the camera and lens in extreme temperature environments. The simulation results showed that these designs were effective to improve the stability of the metrology system

The Dark Energy Spectroscopic Instrument (DESI) is a project in construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs covering a 360 - 980 nm passband with a spectral resolution (λ/Δλ) between 1500 and 4000. The spectrograph uses two dichroic beam splitters to separate the flux among three spectral cameras, each with a volume phase holographic grating and lens system that focuses onto a charge coupled device detector. We describe the spectrograph, its system requirements, design and construction.

The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover a 1.3 degree diameter field with 2394 fibers to complement the imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final positioning accuracy between the fibers and observing targets of PFS is required to be less than 10 μm. The metrology camera system (MCS) serves as the optical encoder of the fiber positioners for the configuring of fibers. MCS provides the fiber positions within a 5 microns error over the 45 cm focal plane. The information from MCS will be fed into the fiber positioner control system for the closed loop control. MCS locates at the Cassegrain focus of Subaru telescope to cover the whole focal plan with one 50M pixel Canon CMOS camera. It is a 380 mm aperture Schmidt type telescope which generates uniform spot size around 10 µm FWHM across the field for reasonable sampling of the point spreading function. An achromatic lens set is designed to remove the possible chromatic error due to the variation of the LED wavelength. Carbon fiber tubes are used to provide stable structure over the operation conditions without focus adjustments. The CMOS sensor can be read in 0.8 s to reduce the overhead for the fiber configuration. The positions of all fibers can be obtained within 0.5 s after the readout of the frame. This enables the overall fiber configuration to be less than 2 minutes. MCS is installed inside a standard Subaru Cassgrain Box. All components generate heat are located inside a glycol cooled cabinet to reduce the possible image motion due to the heat. The integration of MCS started from fall 2017 and it was delivered to Subaru in April 2018. In this report, the performance of MCS after the integration and verification process in ASIAA and the performance after the delivery to Subaru telescope are presented.

We present the results of an automated fibre optic test bench constructed at the University of Victoria as part of the Maunakea Spectroscopic Explorer (MSE) Fibre Transmission System (FiTS). In preparation for MSE-FiTS, we have begun characterizing the focal ratio degradation (FRD) of candidate multi-mode fibres with the ultimate goal of testing all 4000 MSE fibres. To achieve this, we have built an optical bench to perform an automated version of the collimated beam test. Herein we present the design of the bench and discuss the automation of components by introducing the Big FiTS Fibre Wrapper (Big FFW), our open-source automation software. We conclude with the results of tests performed using the Big FFW on a sample of candidate fibre, comparing the Big FFW results against those found using manual methods. Our results suggest that the candidate MSE fibre meets the science requirement of < 5% FRD at f /2 and find less than 1% disagreement between both measurement methods.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 deg² will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. A consortium of Aix-Marseille University (AMU) and CNRS laboratories (LAM, OHP and CPPM) together with LPNHE (CNRS, Universities Pierre et Marie Curie and Paris-Diderot) and the WINLIGHT Systems company based in Pertuis (France), are in charge of integrating and validating the performance requirements of the full spectrographs. This includes the cryostats, shutters and other mechanisms. The first spectrograph of the series of ten has been fully tested and the performance requirements verified for the following items: focus, image quality, straylight, stability, detector properties and throughput. We present the experimental setup, the test procedures and the results.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq. deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fibre optic positioners. The fibres in turn feed ten broad-band spectrographs. We describe the design, production, quality assurance procedures and performance of the DESI slit assemblies.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryonic Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fibre optic positioners. The fibres in turn feed 10 broad-band spectrographs. We will describe the design and production progress on the fibre cables, strain relief system and preparation of the slit end. In contrast to former projects, the larger scale of production required for DESI requires teaming up with industry to find a solution to reduce the time scale of production as well as to minimise the stress on the optical fibres.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We will describe the design and performance of the DESI fiber system. This includes 5000 custom positioner fiber assemblies, spliced to 10 fiber cables terminated in a slit array.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We will describe the design and performance of the DESI fiber system which consists of 5000 custom positioner fiber assemblies that are installed into 5000 robotic fiber positioners.

The Fiber Optic Cable and Connector System, FOCCoS, is a set of optical cables to feed the Prime Focus Spectrograph, PFS, for Subaru telescope [01,02]. The extremity responsible for delivering light to spectrographs is called, FCA, Fiber Cable A. Cable A is the cable installed at the Spectrograph side and consists of the Fiber Slit Assembly, FSA, the routing with its support and the Fiber Input Assembly, FIA. FSA is composed of a set of optical fibers arranged linearly on the Slit device and supported by the Frame, protected by segmented tubes and routed between strain relief boxes and the connection interface. FIA is composed by the Connector Bench (Gang Connector) that allow connection with Cable B, at the Subaru Telescope interface, to receive light from Cable C where the fibers end is coupled with microlens. As four Spectrographs are considered for PFS/Subaru, four units of Cable A are necessary. In this paper, we present in details of a complete FCA to be installed in the spectrograph bench. We discuss about the general design, methods used to manufacture the involved devices.

The focal ratio degradation effects on optical fibers, technically referred to as FRD, has been the subject of intense studies since the beginning of the use of optical fibers in the construction of instruments applied in astronomy. A number of studies attempt to relate FRD to light loss in the optical system and other studies attempt to qualify and quantify FRD as a function of the stress induced during assembly of the structures supporting the ends of the optical fibers. In this work, we present a large-scale study to characterize FRD in all the fibers that make up the cables of the FOCCoS, Fiber Optical Cable and Connectors System project. FOCCoS, has the main function of capturing the direct light from the focal plane of Subaru Telescope using 2400 optical fibers, each one with a microlens in its tip, and conducting this light through a route containing connectors to a set of four spectrographs. The optical fiber cable is divided in 3 different segments called Cable A, Cable B and Cable C. Multi-fibers connectors assure precise connection among all optical fibers of the segments, providing flexibility for instrument changes. Our study provides procedures and methods to analyze the effects of FRD on all cable segments for each type of termination involved. Special attention is devoted to the understanding of how angular deviations between the input surface of the fiber and the test beam can significantly influence the calculation of FRD in optical fibers.

The Maunakea Spectroscopic Explorer (MSE) is a next-generation observatory, designed to provide highly multiplexed, multi-object spectroscopy over a wide field of view. The observatory will consist of (1) a telescope with an 11.25 m aperture, (2) a 1.5 square-degree science field of view, (3) fibre optic positioning and transmission systems, and (4) a suite of low (R=3000), moderate (R=6000) and high resolution (R=40,000) spectrographs. The Fibre Transmission System (FiTS) consists of 4332 optical fibres, designed to transmit the light from the telescope prime focus to the dedicated spectrographs. The ambitious science goals of MSE require the Fibre Transmission System to deliver performance well beyond the current state of the art for multi-fibre systems, e.g., the sensitivity to observe magnitude 24 objects (@ SNR=2) over a very broad wavelength range (0.37 – 1.8 μm) while achieving relative spectrophotometric accuracy of < 3% and radial velocity precision of 20 km/s (@ SNR=5). This paper details the design of the FiTS fibre system. It places FiTS into context with existing and planned spectroscopic facilities, such as Subaru/PFS, KPNO/DESI, ESO/4MOST and Gemini/GRACES. The results and lessons learned from GRACES are particularly applicable, since FiTS and GRACES share many team members, including industrial partner FiberTech Optica (Kitchener, ON). The FiTS system consists of 57 identical fibre cables. These cables have been designed to be modular, facilitating efficient construction and automated acceptance testing. Each cable consists of 76 fibres, including 57 fibres feeding light to the low and moderate resolution spectrographs and 19 fibres feeding the high-resolution spectrographs. Thus, the MSE/FiTS consists of 4332 fibres in total. Novel construction techniques utilizing continuous high-NA (f/2) fibres, pioneered by FiberTech Optica, are outlined and test results showing < 5% focal ratio degradation (FRD) in V-band are presented. The effect on FRD from varying the input f/# is also shown. Where test data is unavailable, system error budgets have been created to assess design choices on options such as fibre material, anti-reflection coatings, and fibre-optic connectors

FOCCoS, "Fiber Optical Cable and Connector System", is a part of subsystem of Prime Focus Spectrograph”, for Subaru telescope. FOCCoS are divided in 3 different segments called Cable A, Cable B and Cable C. Multi-fibers connectors assure precise connection among all optical fibers of the segments, providing flexibility for instrument changes. Cable B is permanently installed at Subaru Telescope structure starting in a Connector Bench device and finishing at another different Connector Bench device. By this way, Cable B represent a link between the light entrance, from Cable C, and the light delivery, to Cable A. This cable will be routed to minimize the compression, torsion and bending caused by the cable weight and telescope motion. In this work, we present the current stage of development of Cable B as well as the detailing of its structures. In addition, we present the optical fiber cabling methodology and the test procedures involved in its characterization. A prototype of Cable B was constructed to help us to better understanding the real situation and was tested at Subaru Telescope.

We present fore-optics and calibration unit design of Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS). DOTIFS fore-optics is designed to modify the focal ratio of the light and to match its plate scale to the physical size of Integral Field Units (IFUs). The fore-optics also delivers a telecentric beam to the IFUs on the telescope focal plane. There is a calibration unit part of which is combined with the fore-optics to have a light and compact system. We use Xenon-arc lamp as a continuum source and Krypton/Mercury-Neon lamps as wavelength calibration sources. Fore-optics and calibration unit shares two optical lenses to maintain compactness of the overall subsystem. Here we present optical and opto-mechanical design of the calibration unit and fore-optics as well as calibration scheme of DOTIFS.

A novel concept for the calibration of multi object fiber-fed spectrographs is described for the 4MOST instrument. The 4MOST facility is foreseen to start science operations in 2022 at the ESO VISTA telescope. The calibration system provides intensity, wavelength and resolution calibrations for the 4MOST spectrographs. The heart of the system is a combination of a bright broad band lamp and a Fabry-Perot etalon. The lamp is able to provide sufficient flux to illuminate the VISTA focal plane and the Fabry-Perot etalon provides a regular comb of spectral lines. The Fabry-Perot etalon can be moved in and out of the optical beam to choose between intensity and spectral calibrations. A fiber bundle of 156 fibers is guided to the VISTA spider arms where each fiber is connected to a small integrating sphere. The integrating spheres are attached to the bottom side of the four VISTA telescope spider struts and provide unvignetted illumination of the telescope. The exit port of the integrating spheres is projected on the VISTA focal plane with a small collimator lens. The integrating spheres assure a uniform illumination of the focal plane and are insensitive to FRD effects of the input fibers due to motion and stress during telescope movements. The calibration system illumination only originates from the telescope spiders and therefore the telescope pupil is not fully filled. The calibration system uses the azimuthal scrambling properties of the fibers that connect the telescope focal plane and the spectrometers to completely fill the spectrograph pupil.

The Maunakea Spectroscopic Explorer (MSE) project will transform the CFHT 3.6m optical telescope to a 10m class dedicated multi-object spectroscopic facility, with an ability to measure thousands of objects with three spectral resolution modes respectively low resolution of R≈3,000, moderate resolution of R≈6,000 and high resolution of R≈ 40,000. Two identical multi-object high resolution spectrographs are expected to simultaneously produce 1084 spectra with high resolution of 40,000 at Blue (401-416nm) and Green (472-489nm) channels, and 20,000 at Red (626-674nm) channel. At the Conceptual Design Phase (CoDP), different optical schemes were proposed to meet the challenging requirements, especially a unique design with a novel transmission image slicer array, and another conventional design with oversize Volume Phase Holographic (VPH) gratings. It became clear during the CoDP that both designs presented problems of complexity or feasibility of manufacture, especially high line density disperser (general name for all kinds of grating, grism, prism). At the present, a new design scheme is proposed for investigating the optimal way to reduce technical risk and get more reliable estimation of cost and timescale. It contains new dispersers, F/2 fast collimator and so on. Therein, the disperser takes advantage of a special grism and a prism to reduce line density on grating surface, keep wide opening angle of optical path, and get the similar spectrum layout in all three spectral channels. For the fast collimator, it carefully compares on-axis and off-axis designs in throughput, interface to fiber assembly and technical risks. The current progress is more competitive and credible than the previous design, but it also indicates more challenging work will be done to improve its accessibility in engineering.

WEAVE is the new wide-field spectroscopy facility for the prime focus of the William Herschel Telescope on La Palma in the Canary Islands, Spain. It is a multi-object “pick-and-place” fibre-fed spectrograph with a 960 fibre multiplex behind a new dedicated 2° prime focus corrector. We provide an update on the fibre positioner's technical progress. The hardware has been fully assembled and integrated with its control system for testing. We have made initial calibrations and are starting to move test fibres. In the near future we will dismantle for final modifications and surface anodising, before final reassembly and full fibre installation.

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad- band spectrographs. We will present an overview of the mechanical structure that sits atop the Mayall Serrurier trusses and supports the six lenses, the Atmospheric Dispersion Compensator (ADC) rotator and the Focal Plane Assembly. This mechanical structure has already been built, we will describe the main technical requirements and challenges during the construction.

In this paper we present recent progress on the Australian Astronomical Observatory’s AESOP2 fiber positioner for 4MOST (on VISTA). As an evolution of the Echidna “spine” technology used for FMOS (on Subaru), AESOP has challenging requirements to position 2,448 fibers in parallel, within 1 minute, to an accuracy of < 10 um RMS. AESOP successfully passed ESO’s official final design review and manufacturing has commenced. We present performance results from the first batch of newly-manufactured positioners and also report on how the AESOP project is tracking in terms of schedule, budget and risk.

We describe the design of the Commissioning Instrument for the Dark Energy Spectroscopic Instrument (DESI). DESI will obtain spectra over a 3 degree field of view using the 4-meter Mayall Telescope at Kitt Peak, AZ. In order to achieve the required image quality over this field of view, a new optical corrector is being installed at the Mayall Telescope. The Commissioning Instrument is designed to characterize the image quality of the new optical system. The Commissioning Instrument has five commercial cameras; one at the center of the focal surface and four near the periphery of the field and at the cardinal directions. There are also 22 illuminated fiducials, distributed throughout the focal surface, that will be used to test the system that will map between the DESI fiber positioners and celestial coordinates. We describe how the commissioning instrument will perform commissioning tasks for the DESI project and thereby eliminate risks.

The Visible Integral Field Replicable Unit Spectrograph (VIRUS), the instrument for the Hobby Eberly Telescope Dark Energy Experiment (HETDEX), consists of 78 replicable units, each with two integral field spectrographs. The VIRUS design takes advantage of large-scale replication of simple units to significantly reduce engineering and production costs of building a facility instrument of this scale. With VIRUS being 156 realizations of the same spectrograph, this paper uncovers the statistical variations in production of these units. Lab relative throughput measures are compared with independently measured grating and optical element performance allowing for potential diagnosis for the cause of variation due to spectrograph elements. Based on variations in performance of individual optical components, throughput curves are simulated for 156 VIRUS spectrograph channels. Once delivered, each unit is paired with a fiber bundle and throughput measurements are made on sky using twilight flats. We compare throughput variance from on-sky measurements to the simulated throughputs. We find that the variation in throughput matches that predicted by modeling of the individual optics performance. This paper presents the results for the 40 VIRUS units now deployed.

LAMOST requires fast and accurate alignment of 4000 optical fiber units on a 1.75m-diameter convex focal plane to simultaneously observe 4000 targets, and the positioning accuracy of the unit is very demanding. But in fact there are a variety of factors such as motor motion error, machining error, assembly error, etc. which may lead to great positioning error. Moreover gear meshing transmission at the eccentric shaft and the anti-backlash spring may also cause greater positioning accuracy error. Besides,the inevitable gap between the center shaft and the bearing leads to motion error of the rotation mechanism, which also affects the precise positioning of the optical fiber. Therefore, in this paper, model and simulate the eccentric shaft basing on virtual prototype ADAMS set parameters and change the axial restraint of the gear, then obtain the axial movement curve. Design 9 groups of comparative tests through orthogonal experimental design.The results in case that: (1) The maximal movement of the gear at the eccentric shaft is within the allowable range, and has little effect on the unit positioning accuracy; (2) The overall error of the unit shaft clearance is in the range of -0.06deg/s -0.2deg/s, which leads to low positioning accuracy that may not meet the observation requirement. This research provides a theoretical basis for the design of a new generation high-precision positioning unit in the future.

The 4-metre Multi-Object Spectroscopic Telescope (4MOST) instrument uses 2436 individually positioned optical fibres to couple the light of targets into its spectrographs. The metrology system determines the position of the back-illuminated fibres on the focal surface of the telescope. It consists of 4 identical cameras that are mounted on the spider vanes of the secondary mirror of the VISTA telescope and look through the entire optical train, including M1, M2 and the WFC/ADC unit. Here, we present an exhaustive study on the expected centroiding errors, including but not limited to lens fabrication errors, seeing, mirror distortions and parallax effects.

4MOST, the 4m Multi Object Spectroscopic Telescope, is an upcoming optical, fibre-fed, MOS facility for the VISTA telescope at ESO's Paranal Observatory in Chile. Its main science drivers are in the fields of galactic archeology, highenergy physics, galaxy evolution and cosmology. The preliminary design of 4MOST features 2436 fibres split into lowresolution (1624 fibres, 370-950 nm, R < 4000) and high-resolution spectrographs (812 fibres, three arms, ~44-69 nm coverage each, R < 18000) with a fibre positioner and covering an hexagonal field of view of ~4.1 deg². The 4MOST consortium consists of several institutes in Europe and Australia under leadership of the Leibniz-Institut für Astrophysik Potsdam (AIP). 4MOST is currently in its Final Design Phase with an expected start of science operations in 2022. In this paper, the final optomechanical design and performances of 4MOST Low Resolution Spectrograph will be presented. It has been designed by CRAL for 4MOST FDR held in May, 2018. Special emphasis will be put on the technical requirements of individual optics and the mechanical design with its associated FEA.

The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project for Subaru telescope includes four identical spectrograph modules fed by 600 fibers each. This paper presents the integration, alignment and test procedures for the first spectrograph module composed by an optical entrance unit that creates a collimated beam and distributes the light to three channels, two visible and one near infrared. In particular, we present the performance of the single Red channel module. Firstly, we report on the measured optical performance: optical quality and ghost analysis. We also report on the thermal performance of the visible camera cryostat. Finally, we describe the software used to control and monitor the instrument.

The 4MOST¹ instrument is a multi-object-spectrograph for the ESO-VISTA telescope. The 4MOST long fiber feed links the AESOP² fiber positioner to two low-resolution spectrographs (1624 fibers) and one high-resolution spectrograph (812 fibers). In addition to the 2436 science fibers, the system includes guide fiber bundles, metrology fiducial fibers and simultaneous calibration fibers for the spectrographs. To validate the design approaches, including fiber connectors and cable rotator, pre-production fiber cables have been built and evaluated. This paper presents the near final design of the fiber feed subsystem and its performance results pertaining to throughput homogeneity, focal ratio degradation, and connector loss of the pre-production cables.

The Hobby-Eberly Telescope Wide Field Upgrade includes deployment of the fiber-fed VIRUS and LRS2 spectrographs. In total, over 35,000 optical fibers of around 20m lengths are coupled to the telescope. This paper discusses the routing of those fibers, the hardware for securing them, and their deployment. Routing of the fibers to accommodate telescope motion while minimizing length and bend is presented. Hardware solutions for securing the fibers with details of the input and output terminations are included. Operations to safely install the fibers on the telescope are also covered.

The Maunakea Spectroscopic Explorer (MSE) Project is a planned replacement for the existing 3.6-m Canada France Hawaii Telescope (CFHT) into a 10-m class dedicated wide field highly multiplexed fibre fed spectroscopic facility. MSE seeks to tackle basic science questions ranging from the origin of stars and stellar systems, Galaxy archaeology at early times, galaxy evolution across cosmic time, to cosmology and the nature of dark matter and dark energy. MSE will be a primary follow-up facility for many key future photometric and astrometric surveys, as well as a major component in the study of the multi-wavelength Universe. The MSE is based on a prime focus telescope concept which illuminate 3200 fibres or more. These fibres are feeding a Low Moderate Resolution (LMR) spectrograph and a High Resolution (HR). The LMR will provide 2 resolution modes at R>2500 and R>5000 on a wavelength range of 360 to 950 nm and a resolution of R>;3000 on the 950 nm to 1300 nm bandwidth. Possibly the H band will be also covered by a second NIR mode from ranging from 1450 to 1780 nm. The HR will have a resolution of R>39000 on the 360 to 600 nm wavelength range and R>;20000 on the 600 to 900 nm bandwith. This paper presents the LMR design after its Conceptual Design Review held in June 2017. It focuses on the general concept, optical and mechanical design of the instrument. It describes the associated preliminary expected performances especially concerning optical and thermal performances.

The VIRUS2 Instrument is the next generation replicated integral field spectrograph for the 2.7m Harlan J. Smith Telescope at the McDonald Observatory. The instrument extends the technological advances from VIRUS and HET LRS-2 instruments to offer higher spectral resolution of R<2000 over a broader wavelength coverage from 370nm to 1000nm and a larger sky area of 2 arcmin diameter in a single shot with spatial sampling of 2.6 arcsec. The instrument also utilizes fiber integral field units (IFUs) coupled with micro-focal reducers to offer nearly 100% fill-factor on sky. VIRUS2 is the successor of the Mitchell Spectrograph (aka. VIRUS-P) on the HJST. T ere is also a potential for its scientific use on the Giant Magellan Telescope as an early phase instrument.

Hector is a multi-IFU spectrograph in phase-A building for the Anglo-Australian Telescope (AAT) using fibers. Its goal is to observe 30,000 galaxies when fully complete. It is a follow up instrument of SAMI which has 13 IFUs 15" wide. The full project will have a 2 degree field corrector and at least 3 spectrographs. The IFUs are hexabundles 15" to 30" wide made of bare fibers with no buffer tightly packed and fused together to minimize the surface losses between their cores. Many different transparent spectrograph designs were studied covering a large parameter space. An important trade-off study was between the use of microlenses on the slit or just bare fibers. Microlenses have disadvantages but permit considerable simplification of the collimator by making the beam very slow. With microlenses, the collimator can be a unique spherical plano-convex lens significantly smaller than the mirror that would be needed in a reflective design. In the first part of the design, 26 different cameras where designed to cover the parameter space for 2k x 2k, 2k x 4k, or 4k x 4k detectors, and for 50, 75 or 100 micron fiber cores, with or without microlenses, with a triplet in the camera or a doublet plus singlet, and with a maximum wavelength of 1 or 1.05 microns. Not all combinations were designed but for each parameter there are at least two representative cameras with all other parameters identical. A preliminary cost estimate was made for the most promising designs which permitted to reduce them to 3 set of parameters for detailed designing, then to 2 with 4k x 4k detectors and 100 micron fiber cores. One design was made to be simple and low risk with only singlets in the collimator and cameras, the other complex with a mirror in the collimator, doublets and triplets, and innovations that could give better performance at a lower cost but with increased risk. For similar cost, the safe design has lower performances but also lower risks than the complex design. In the final stage of design, a trade-off hybrid design that keep the best of both ended being much cheaper, lower risk and with a shorter schedule than the complex design and with much better performances than the safe design. For this design, a model of the cost using lens diameter, glass cost and asphere complexity as the parameters was directly included in the Zemax Merit Function leading to significant cost improvement at fixed performances. The final design has 2 cameras covering 372 nm to 778 nm at an average resolution of 0.12 nm and able to accommodate about 1000 fibers of 1.6" core diameter. The collimator has 4 lenses and the cameras 4 and 5. There are no microlenses on the slit. The spectrograph can be upgraded with a third camera extending the coverage to 1000 nm.

With the development of the spectral survey project, the miniaturization, high density, integration and high precision positioning requirements of the fiber positioning unit have become a general trend, which also puts forward higher technical requirements and challenges for the optical fiber positioning system. At the same time, fiber positioning technology also expects to achieve high-precision real-time monitoring and feedback system to form an effective closedloop control. This propose a the concept design of the fiber positioning real-time monitoring system with four-quadrant detector based on the parallel controllable fiber positioning technology of LAMOST.

Projects such as "The Dark Energy Spectroscopic Instrument” (DESI) [4] or ”The Multi Object Optical and Near-infrared Spectrograph” (MOONS ) [5] are developing spectrographs, composed of more than thousand of optical fibers in a confined hexagonal focal plane, to study the evolution of the universe. Such systems allow fast reconfiguration of the fibers as they are moved simultaneously to their assigned target by a 2-arm positioner within an short interval of time. Moreover, astronomers prioritize the observation of some objects over those that hold less information, creating a hierarchy of importances or priorities. In a scenario where not all the positioners can reach their targets, It is important to ensure the observation of the high-priority targets. In previous works, a decentralized navigation function from the family of potential fields was used for collisionfree coordination. While it guarantees convergence of all the positioners to their targets for DESI [1,2], it fails at planning motion for positioners in MOONS [3]. The reason is that the second arm of the positioners in MOONS is two times the length of the first arm. Covering a larger working space, they are prone to deadlocks, a situation where two or more positioners are blocked by each other and so unable to reach their targets. In this paper and in the framework of MOONS project, we present our new approach to integrate assigned priorities with the decentralized navigation functions to reduce the deadlocks situations. For this purpose, we regulate the movements of the positioners using a finite-state machine combined with distance-based heuristics. Each positioner’s state dictates its behaviors with respect to other positioners. Distance-based heuristics limit the states transition when a positioner is interacting with its adjacent positioners to localize possible deadlock situations. The advantage of this method is its simplicity as it relies on local interaction of positioners, keeping the complexity of the algorithm quasilinear. In addition, since it does not depend on the positioner’s geometry, it is also scalable to other positioner kinematics. We developed a motion planning simulator with a graphic interface in python to validate the coordination of the positioners with assigned priorities. As a result, the number of positioners converging to their targets improve from 60-70% to 80-95%. The computation time of the trajectories increases slightly due to the new layer of algorithm added for deadlocks prevention.

Wide-Field Optical Spectrograph (WFOS) is an optical multi-object spectrograph and one of the first-light instruments of Thirty Meter Telescope (TMT). The WFOS development team has studied three new instrument concepts. One is a fiber-based spectrograph, and other one is a spectrograph using image slicers (Slicer-WFOS). The last one is the simple multi-slit spectrograph. Japanese WFOS team has conducted conceptual studies on Slicer-WFOS in collaboration with California Institute of Technology. Slicer-WFOS has only one VPH grating for each red and blue arm. The gratings offer R~1,500 for a simple 0.″75-width slit. The image slicer divides an object image into three slices and the higher spectral resolution of R~4,500 can be achieved using the same grating. In this proceeding paper, we report our design studies on the slicer module.

HARMONI is a first-light visible and near-IR integral field spectrograph of ESO’s Extremely Large Telescope (ELT) which will sit on top of Cerro Armazones, Chile. A Single Conjugate Adaptive Optics (SCAO) sub-system will provide diffraction-limited spectral images in a Nyquist-sampled 0.61 × 0.86 arcsec field of view, with a R=3000-20000 spectral resolution. Inside the instrument, a High Contrast Module (HCM) will add an essential high-contrast imaging capability for HARMONI to spectrally characterize young giant exoplanets and disks with flux ratio down to 1e-6 at 0.1-0.2” from their star. The HCM uses an apodized pupil coronagraph to lower the intensity of the diffracted starlight and limit the dynamic range on the detector, and an internal wavefront sensor to calibrate non-common path aberrations. This communication first summarizes the basic technical requirements of the HCM, then describes its optical and mechanical designs, and presents expected performance in terms of achievable contrast, image quality and throughput. Elements of the development and test program are also given.

The first generation of ELT instruments will include an optical-infrared High Resolution Spectrograph, conventionally indicated as ELT-HIRES. This paper describes the optical design and overall architecture of the instrument whose main capabilities can be summarized as follows. – Fibers fed specrographs with resolving power R=100,000 (HR-modes), R=150,000 (UHR-modes) and R=20,000 (MR-modes). – Simultaneous wavelength coverage from 400 nm to 1800 nm; extendable to 300-2400 nm. – Spectrometers with fixed configurations and without moving optical parts. – Maximum size of entrance apertures ideal for seeing limited observations. – Many observing modes, including seeing-limited single-object spectroscopy, multi-objects medium resolution spectroscopy and IFU observations with different spatial scales, down to the diffraction limit of the ELT telescope. – Observing modes defined and selected in interfaces outside of the spectrographs. – Modular design compatible with a minimal baseline that can be subsequently expanded and upgraded.

METIS, a mid-infrared imager and spectrograph for the wavelength range 2.9–19μm (astronomical L-, M-, N- and Q-band), will be one of the first three science instruments at the European Extremely Large Telescope (E-ELT). It will provide diffraction limited imaging, coronagraphy, high resolution integral field spectroscopy and low and medium resolution slit spectroscopy. Within the international METIS consortium, the 1st Institute of Physics of the University of Cologne in Germany is responsible for the design, manufacturing, integration and qualification of the Warm Calibration Unit (WCU) of the instrument. The WCU will be a self-contained unit operating at ambient temperature outside of the voluminous METIS dewar, feeding a variety of optical calibration and alignment signals into the optical path of METIS. The functionalities of the WCU will be used for routine daily daytime calibrations after astronomical observing nights and verification of the internal alignment of METIS during assembly, integration and verification (AIV). In this contribution we present the preliminary optical design and principle of operation of the WCU in its current state of the preliminary design phase of METIS.

The first generation of ELT instruments will include an optical-infrared High Resolution Spectrograph, conventionally indicated as ELT-HIRES. This paper describes the optical design and overall architecture of the Integral Field Unit (IFU) that will fed the spectrograph. The module have the possibility to change the spaxel dimension thanks to a series of reflection mirrors and using a fast tip tilt mirror the position of the re-imaged foci on the fiber bundles can be adjusted looking at the focus image that is visible using a fiber viewer IR camera.

We present the consolidated scientific case for multi-object spectroscopy with the MOSAIC concept on the European ELT. The cases span the full range of ELT science and require either ‘high multiplex’ or ‘high definition’ observations to best exploit the excellent sensitivity and wide field-of-view of the telescope. Following scientific prioritisation by the Science Team during the recent Phase A study of the MOSAIC concept, we highlight four key surveys designed for the instrument using detailed simulations of its scientific performance. We discuss future ways to optimise the conceptual design of MOSAIC in Phase B, and illustrate its competitiveness and unique capabilities by comparison with other facilities that will be available in the 2020s.

ELT-HIRES is the high resolution and ultra-stable Echelle spectrograph for the ELT. It has been conceived as a modular instrument provided with two independent spectrometers (the baseline design) and a possible extension to four, each of them optimized to cover a fixed spectral range. The role of the fibers is essential to provide the required ultrastability. Placed at the Nasmyth focus of the ELT, the HIRES fiber link transfers the light from the focal plane to the spectrographs. Each observing modes will be use a unique and independent group of fibers (bundle). The HIRES modular design makes it possible to have new observing modes just with the addition, removal or change of the specific bundles. From a functional point of view the HIRES fiber link subsystem performs some other important tasks, such as dicing the field of view, improving the system stability and providing a uniformly illuminated slit for spectrographs. It is a key subsystem for the instrument and represents a significant technological challenge. The technical requirements, conceptual design and technologies to be used are discussed in this paper. The current status of the subsystem, and future plans are also addressed.

MICADO is the Multi-AO Imaging Camera for Deep Observations, a first light instrument for the Extremely Large Telescope (ELT). It will provide the ELT with diffraction limited imaging capacity over a ~53-arcsec field of view, while operating with the Multi-Conjugate Adaptive Optics (MCAO) module MAORY (0.8-2.5 μm). Here, we present the design status of the MICADO derotator, which at the same time serves (i) as crucial mechanical interface between the cryo-opto-mechanical camera assembly and the instrument support structure and (ii) as high-precision image and wavefront sensor derotator to allow for 50 µas astrometry over the entire MCAO corrected field. Additionally, first test results are presented which were obtained with a derotator prototype based on a scaled 1:2 test bearing. The derotator test stand is essential to explore the limitations of the preferred bearing type in the context of the given requirements. The technical difficulties addressed by the design include: (i) design of adequate mechanical interfaces to minimize mass, deformation and the effect of the warping moment on the bearing and (ii) analysis of the friction-related stick-slip effects at low tracking velocities for the implementation of a suitable position-velocity closed-loop control system. Furthermore, our prototype setup is used to develop and test the required control concept of this high-precision application.

The paper describes the preliminary design of the MICADO calibration assembly. MICADO, the Multi-AO Imaging CAmera for Deep Observations, is targeted to be one of the first light instruments of the Extremely Large Telescope (ELT) and it will embrace imaging, spectroscopic and astrometric capabilities including their calibration. The astrometric requirements are particularly ambitious aiming for ~ 50 μas differential precision within and between single epochs. The MICADO Calibration Assembly (MCA) shall deliver flat-field, wavelength and astrometric calibration and it will support the instrument alignment to the Single-Conjugate Adaptive Optics wavefront sensor. After a complete overview of the MCA subsystems, their functionalities, design and status, we will concentrate on the ongoing prototype testing of the most challenging components. Particular emphasis is put on the development and test of the Warm Astrometric Mask (WAM) for the calibration of the optical distortions within MICADO and MAORY, the multiconjugate AO module.

MICADO, the Multi-AO-Imaging-Camera and Spectrometer for Deep Observations, is one of the first light instruments for the future 40 m class Extremely Large Telescope (ELT). MICADO utilizes the advanced laser guide star multiconjugate adaptive optics system MCAO developed by the MAORY consortium and the jointly developed singleconjugate adaptive optics system (SCAO). We present an overview on the conceptual design of the MICADO Cold Optical Instrument (COI) which comprises the infrared focal plane imager with its 3 x 3 4k² HgCdTe detector array and a compact cross-dispersing slit spectrometer operating in the spectral range of 0.8 to 2.4 μm. High contrast imaging is enabled via a classical configuration of coronagraph and Lyot stops. The paper summarizes the MICADO COI interchangeable optics, its cryogenic implementation together with the modular opto-mechanical configuration of the cryo-mechanisms and the cryo-vacuum cooling system, which consists of a continuous LN2 flow cryostat.

The GMT-Consortium Large Earth Finder (G-CLEF) is one of the first instrument for the Giant Magellan Telescope (GMT). The G-CLEF is a fiber fed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. The G-CLEF Flexure Control Camera (FCC) is included as a part in the G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within the GCFEA. The five optical components constituting the FCC are aligned on a common optical bench. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimaging camera barrel, and a detector module. The collimator receives the beam reflected by the fiber mirror and consists of a triplet lens. The neutral density filters are located just after the collimator to make it possible a broad range star brightness as a target or a guide. The tent prism focus analyzer is positioned at a pupil produced by the collimator and is used to measure a focus offset. The reimaging camera barrel includes two pairs of doublet lenses to focus the beam onto the CCD focal plane. The detector module is composed of a linear translator and a field de-rotator. In this article, we present the optical and mechanical detailed designs of the G-CLEF FCC.

MICADO, the Multi AO Imaging Camera for Deep Observations, is one of the first light instruments for the ELT, currently under construction by the European Southern Observatory (ESO) on Cerro Armazones in Chile. It is built by a huge consortium with partners from the Netherlands, Austria, France, Italy, Finland and Germany under the lead of the Max-Planck-Institute for extraterrestrial Physics in Garching. The instrument will operate in the NIR wavelength range, thus is developed as a cryogenic instrument to work under vacuum conditions. It can be used as an imaging camera in a high and low resolution mode, a spectrometer and also as a coronagraph. For calibration purposes a so called ”pupil imager” mode will also be implemented. To switch between the operational modes MICADO will use the MSM to insert different optical modules to the fixed components of the High Resolution Imager (HRI) inside the cryostat. All moving parts have to operate under vacuum and at cryogenic temperatures. The MSM consists of a rotating platform, where the optical modules are mounted on. To lower the friction inside the mechanism we decided to use several small bearings to support the platform instead of a central big one. The small bearings are placed in a way, that the movement of the platform is limited to a rotation. Some of the bearings will be preloaded by springs to take also CTE differences or temperature gradients during the cool down and warm up phases into account. The mechanism will be driven by a cryogenic Phytron stepper motor with an integrated planetary gear box. Switches will be used to limit the rotation of the platform to the necessary range. Because of the challenging requirements on repositioning of the optical modules inside the science beam, we will use an indent mechanism. We are still investigating if the indent mechanism has to be actively driven or can be implemented as a passive version. The necessary optics to switch between the operational modes are designed as individual pre-aligned modules, each with a defined mechanical and thermal interface to the rotating platform. The Low Resolution Imager (LRI) consists of two flat mirrors, blocking some of the fixed components of the HRI. The spectrometer will use two reflective gratings, one acting as the main and one as a cross disperser. The cross disperser separates the overlaying orders on the focal plane array. The pupil viewer consists like the LRI module of two flat mirrors and an additional lens imaging the pupil to the focal plane. In this paper we will present the current mechanical design and first results of the structural and thermal FEM analyses we performed. We will also highlight first ideas on integration and alignment. A second paper (A. Monna et al., same proceedings) concentrates on the cryogenic setups we perform inside a cryostat to proof proper functionality of the chosen components and designs.

MICADO will equip the ELT with a first light capability for diffraction limited imaging at near-infrared wave- lengths. The instrument’s observing modes focus on various flavours of imaging, including astrometric, high contrast, and time resolved. There is also a single object spectroscopic mode optimised for wavelength coverage at moderately high resolution.1 Due to ESO’s technology standards evolution from VLT to ELT, MICADO will manifest the combined, PLC based soft- and hardware control. The evolution of ESO’s technology design guidelines is on the one hand triggered by the ongoing developments in modern days industry and consumer tech- nology. On the other hand, ELT’s sheer dimensions request increasingly complex and smart solutions onwards controlling and monitoring such huge instruments. ESO’s control concept is based on a two layer approach: PLCs are responsible for low-level hardware control (in a real-time fashion, if necessary), while software running on a Linux workstation implements the astronomic business logic of the control system. Development is eased by the fact that ESO delivers libraries for the control of many standard hardware components. A very interesting feature of this approach is the possibility to run C++ code natively inside a PLC real-time environment. This will be used for the control of complex mechanisms like the MICADO Atmoshperic Dispersion Corrector (ADC). This contribution provides an overview of the key functionality of the instrument focusing on the mechanisms inside the cryostat, and an overview of the cryogenic control. Because of hardware and cryogenic safety reasons, the cryostat control PLC system will be designed as a closed PLC based control system. Hence commands will only be accepted from a human machine interface located next to the cryostat itself. All cryostat parameters and according sensor readings will be published via OpcUA, allowing for full remote cryostat monitoring. In contrast, the instrument control PLC system will interact with the higher level software using the advantages of the industrial OpcUA communication standard and will therefore allow for remote control. Further configuration and commissioning of those mechanisms is made conveniently accessible via this approach. All this is based on ESO’s concept for Line replaceable Units (LRU), which utilizes Beckhoff PLC units to ensure maintainability, availability.

We report on our ongoing efforts to ensure that the MICADO NIR imager reaches differential absolute (often abbreviated: relative) astrometric performance limited by the SNR of typical observations. The exceptional 39m diameter collecting area in combination with a powerful multi-conjugate adaptive optics system (called MAORY) brings the nominal centroiding error, which scales as FWHM/SNR, down to a few 10 μas. Here we show that an exceptional effort is needed to provide a system which delivers adequate and calibrateable astrometric performance over the full field of view (up to 53 arcsec diameter).

We present the preliminary design of the calibration unit of the future E-ELT instrument METIS. This independent subunit is mounted externally to the main cryostat of METIS and will function both as calibration reference for science observations, as well as verification and alignment tool during the AIT phase. In this paper, we focus on describing its preliminary layout and foreseen functionalities, based on the performance requirements defined at system level and the constraints imposed by warm IR background. We discuss the advantage of employing an integrating sphere as common radiation emitter, leading to a novel and versatile design, where the source’s spatio-spectral properties can be varied with high fidelity and repeatability. By combining only few tuneable sources and mechanisms we show how a large instrument such as METIS can be calibrated and tested, without the need of a complex cold calibration unit.

The MICADO instrument support structure has to fulfill two purposes, a) the positioning of the camera in a stand-alone mode with SCAO wavefront sensing at the First Light, and b) when it will be mounted at a later stage downstream of its MCAO facility MAORY. Several reasons led to a change in the instrument support structure from a hexapod into an octopod mount. The paper will address the structural design driven by the telescope and the instrument itself. Tightly linked is the solution to accommodate the bulk of electronics, pumps and cryogenic service devices, which has to corotate closely but separately from the instrument. This co-rotating platform creates issues in the cable wrap in terms of sufficient capacity and large rotation range. Performance assessment will be addressed through a prototype test set-up as well as corresponding Finite-Element-Analysis.

Assembly, Integration, Test and Validation (AIT/V) phases for AO instruments, in laboratory as in the telescope, represent numerous technical challenges. The Laboratoire d’Astrophysique de Marseille (LAM) is in charge of the AIT/V preparation and planning for the MOSAIC (ELT-MOS) instrument, from identification of needs, challenges, risks, to defining the optimal AIT strategy for this highly modular and serialized instrument. In this paper, we present the status of this study and describe several AIT/V scenarios as well as a planning for AIT phases in Europe and in Chile. We also show our capabilities, experience and expertise to lead the instrument MOSAIC AIT/V activities.

The Multi-AO Imaging Camera for Deep Observations (MICADO) is one of the three first light instruments of the Extremely Large Telescope (ELT). Based on the Multi Conjugate Adaptive Optics (MCAO) modul MAORY MICADO offers diffraction-limited near-infrared imagery with a maximum field of view of 53 arcsec. In order to maintain diffraction-limited performance at the edge of the field, a precise image derotator is needed, which compensates the field rotation due to alt-azimuth mount of the telescope. In MICADO a four-point contact ball bearing is foreseen to rotate the cryostat for the compensation of the field rotation. Due to the heavy load and the high precision positioning of the ball bearing a control concept for the derotator is needed. The main challenge of positioning the ball bearing is the handling of friction effects. In this paper we present a control concept based on a velocity feedforward and a PID feedback control to rotate the bearing in the required position performance. At a scaled-down laboratory setup we demonstrate the position accuracy. To further improve the position accuracy we also study an additional friction compensation, which is based on a dynamical friction model.

We present the new LN2 continuous- ow test cryostat of the Universitats-Sternwarte Munchen, procured within the context of the Multi-Adaptive Optics Imaging Camera for Deep Observations (MICADO) for the Extremely Large Telescope. The cryostat will be used to perform tests of mechanical, optical and electronic components at high vacuum condition and cryogenic temperature, for the development of the cryogenic Main Selection Mechanism of the MICADO instrument. In this paper we give an overview of the cryostat design and we report about the temperature stability the cryostat can achieve, as well as the temperature gradient over its cold plate. We also report about the impact of adding extra loads on the system after integrating a cold curved shutter in the cryostat and on characterizing the thermal coupling of cryogenic assemblies.

Harmoni is the ELT's first light visible and near-infrared integral field spectrograph. It will provide four different spatial scales, ranging from coarse spaxels of 60 × 30 mas best suited for seeing limited observations, to 4 mas spaxels that Nyquist sample the diffraction limited point spread function of the ELT at near-infrared wavelengths. Each spaxel scale may be combined with eleven spectral settings, that provide a range of spectral resolving powers from R 3500 to R 20000 and instantaneous wavelength coverage spanning the 0.47 - 2.45 μm wavelength range of the instrument. The consortium consists of several institutes in Europe under leadership of Oxford University. Harmoni is starting its Final Design Phase after a Preliminary Design Phase in November, 2017. The CRAL has the responsibility of the Integral Field Unit design linking the Preoptics to the 4 Spectrographs. It is composed of a field splitter associated with a relay system and an image slicer that create from a rectangular Field of View a very long (540mm) output slit for each spectrograph. In this paper, the preliminary design and performances of Harmoni Image Slicer will be presented including image quality, pupil distortion and slit geometry. It has been designed by CRAL for Harmoni PDR in November, 2017. Special emphases will be put on straylight analysis and slice diffraction. The optimisation of the manufacturing and slit geometry will also be reported.

The Atacama Submillimeter Telescope Experiment (ASTE) 10m aperture telescope has a multicolor camera based on a spiderweb absorber Transition Edge Sensor (TES) bolometer array. We developed a fore-optics module – ‘APol’, to convert 256 pixels of the TES camera into a sensitive imaging polarimeter at 350 ± 25 GHz. We used the simple half-wave plate - wire grid - camera design in APol, and it can cover 7’.5 FOV of ASTE. Here we describe the detailed optical design of APol and present result of the preliminary test carried out with the same optical system and camera at National Astronomical Observatory of Japan (NAOJ) laboratory.

The Thirty Meter Telescope (TMT) is a proposed future generation telescope which will be located on either Maunakea, Hawaii or La Palma in the Canary islands. A thermal-infrared (TIR) imager and spectrometer (MICHI) combined with an adaptive optics system is being investigated as a possible second-generation instrument for this telescope. MICHI has been designed to also have a polarimetry capability in both imaging and low dispersion spectroscopic modes. Using polarization ray tracing in Zemax, we have estimated the instrumental polarization (IP) and crosstalk introduced at the focus of the near- and mid-infrared imaging system. In our calculations, we find that the IP varies from 1.0-0.54% and 0.54-0.42%, whereas the polarization crosstalk varies between 25-4% and 4-0.7%, in the near and TIR regions respectively at the instrument port of MICHI. These values of IP and crosstalk may cause problems during the high absolute accuracy polarization observations. Here we present the polarization effects for the imaging system of MICHI and it impacts on the polarization observations.

The InfraRed Imaging Spectrograph (IRIS) is one of three first light science instruments for the Thirty Meter Telescope (TMT). It will provide dedicated function of imaging and integral field spectroscopic observations in parallel with the assistance of a Narrow Field InfraRed Adaptive Optics System (NFIRAOS). The IRIS imager delivers celestial light to a dual-channel Integral Field Spectrograph (IFS) through a pair of pick-off mirrors in the central field. The IFS creates multi-functional ability to explore the universe in IR (0.84 – 2.4um) with moderate spectral resolution of R=4,000/8,000 and four spaxel scales of 4, 9, 25, 50 milli-arc-seconds (mas). An image slicer serves one of the two spectral channels as its Integral Field Unit (IFU) in two coarse spaxel scales of 25 and 50mas over the continuous science fields of 2.2x1.125 arc-seconds (arcsec) and 4.4x2.25 arcsec respectively. It splits the field to 88 unit systems, and then re-images at two parallel slits in order to take full advantage of the detector (4Kx4K @ 15um). This paper describes a novel all-reflective design of image slicer, which uses a new ‘brick stage’ layout to stagger the adjacent mirrors and deliver image quality close to diffraction limit. The quasi-telecentric optical design gives more friendly interfaces with pre-optics and spectrograph than the conceptual design. Here, more technical issues are discussed to guide the further study on optical performance and fabrication feasibility.

We describe the optical design of GMACS, a multi-object wide field optical spectrograph currently being developed for the Giant Magellan Telescope (GMT). Optical spectrographs for the emerging generation of Extreme Large Telescopes (ELTs) have unique design issues. For example, the combination of both the largest field of view practical and beam widths achieving the desired spectral resolutions force the design of seeing limited ELT optical spectrographs to include large refractive elements, which in turn requires a compromise between the optical performance, manufacturability, and operability. We outline the details of the GMACS optical design subsystems, their individual and combined optical performance, and the preliminary flexure tolerances. Updates to the detector specifications, field acquisition/alignment optics, and optical considerations for active flexure control are also discussed. The resulting design meets the technical instrument requirements generated from the GMACS science requirements, is expected to satisfy the available project budget, and has an acceptable level of risk for the subsystem manufacture and assembly.

LAMOST is a horizontal reflex Schmidt telescope with a large field of view and large aperture. The installation of 5,000 fiber positioning units on a 1.5 m diameter focal panel requires a miniaturized design. This paper uses TI's CC2530 microcontroller and Allegro's A3888 driver chip, combined with ZigBee wireless communication technology, to complete the design of the drive of the fiber positioning unit, and related to the progress of the test, the experimental results meet the design requirements.

MOSAIC is a concept for a multi-object spectrograph for the Extremely Large Telescope (ELT). It is planned to cover the wavelength range from 460 nm to 1800 nm with 5 visible spectrographs and 5 near-infrared spectrographs. The ELT is far from diffraction limited in the visible wavelength range. Rather than developing a large and complex AO system, it was decided that the instrument will be seeing limited in the visible. Spot sizes are therefore about 2.8 mm in diameter in the ELT focal plane, and need to be sampled by multiple fibers with large core diameter. As a result, large optics is required to achieve the science requirements on spectral resolution, bandwidth and multiplex. We work in close collaboration with manufacturers to design an instrument that is feasible and meets the scientific requirements.

HARMONI is a visible and near-infrared (0.5 to 2.45 μm) integral field spectrograph, providing the E-ELT's core spectroscopic capability, over a range of resolving powers from R (λ/Δλ) ~ 3500 to ~18000. The instrument provides simultaneous spectra of ∼32000 spaxels arranged in a sqrt(2):1 aspect ratio contiguous field. The pre-optics take light entering the science cryostat (from the telescope or calibration system), reformatting and conditioning to be suitable for input for the rest of the instrument. This involves many functions, mainly relaying the light from the telescope focal plane to the integral field unit (IFU) focal plane via a set of interchangeable scale changing optics. The pre-optics also provides components including a focal plane mask wheel, cold pupil masks, spectral order sorting filters, a fast shutter, and a pupil imaging capability to check telescope/instrument pupil alignment. In this paper, we present the optical design of the HARMONI pre-optics at Preliminary Design Review and, in particular, we detail the differences with the previous design and the difficulties salved to the Preliminary Design Review.

We present an application of the HIRES End-to-End (E2E) simulator and HIRES Exposure Time Calculator (ETC) to derive a more detailed behavior of the spectrograph efficiency by including physical modeling of diffraction at the echelle grating and the cross-disperser. The result will be used with the Spectral Energy Distributions of calibration lights for wavelength solutions and flat fielding to quantitatively characterize the spectrograph in terms of achieved accuracy. By showing the contribution of photon noise, detector noise and cross talk between adjacent fibers we discuss methods that could be used to determine the overall performance of the instrument, in term of the capability of photon collection as well as especially on the achieved precision on wavelength calibration that translates directly in radial velocity accuracy of the scientific light.

The GMT-Consortium Large Earth Finder (G-CLEF), one of the first light instruments for the Giant Magellan Telescope (GMT), is a fiber-fed, high-resolution echelle spectrograph. G-CLEF is expected to proceed towards fabrication in the coming months. In this paper, we present the current, pre-construction G-CLEF optical design, with an emphasis on the innovative features derived for the spectrograph fiber-feed, the implementation of a volume-phase holographic (VPH)- based cross disperser with enhanced blue throughput and our novel solutions for a multi-colored exposure meter and a flat-fielding system.

High resolution spectroscopy enables the detection of atmospheres of exoplanets. To reach the required radial velocity precision of about 1 m/s, calibration with even more precise sources is mandatory. HIRES will employ several calibration sources, the most important ones are an Laser Frequency Comb (LFC) and Fabry-P´erots (FP). The LFC needs to be filtered with a set of FP. One possible solution is to illuminate this set of FP with a broadband light source and use them as calibrators, when they are not used for filtering the LFC. It has been demonstrated that passively-stabilized FP can perform better than 10 cm/s per night. We give an overview of the currently used FP in different surveys and compare their individual features. For the FP which may be used in HIRES we discuss different configuration. We show that the Finesse and FSR of the FP needs to be optimized with regard to the resolution of the spectrograph and we outline how we aim to fulfill the requirements of HIRES.

HARMONI is an Integral Field Spectrograph (IFS) for ESO’s ELT. It has been selected as the first light spec- trograph and will provide the workhorse spectroscopic capabilities for the ELT for many years. HARMONI is currently at the PDR-level and the current design for the HARMONI IFS consists of a number of spaxel scales sampling down to the diffraction limit of the telescope. It uses a field splitter and image slicer to divide the field into 4 sub-units, each providing an input slit to one of four nearly identical spectrographs. All spectrographs will operate at near infrared wavelengths (0.81-2.45 micrometers), sampling different parts of the spectrum with a range of spectral resolving powers (3300, 7000, 18000). In addition, two of the four spectrographs will have a Visible capability (0.5-0.83 micrometers) operating with seeing-limited observations. This proceeding presents an overview of the opto-mechanical design and specifications of the spectrograph units for HARMONI.

HARMONI is a first-light visible and near-IR integral field spectrograph of ESO’s Extremely Large Telescope (ELT) which will sit on top of Cerro Armazones, Chile. A Single Conjugate Adaptive Optics (SCAO) subsystem will provide diffraction-limited spectro-images in a Nyquist-sampled 0.61 x 0.86 arcsec field of view, with a R=3000-20000 spectral resolution. Inside the instrument, a High Contrast Module (HCM) could give HARMONI the ability to spectrally characterize young giant exoplanets (and disks) with flux ratio down to 10⁻⁶ as close as 100-200mas from their star. This would be achieved with an apodized pupil coronagraph to attenuate the diffracted light of the star and limit the dynamic range on the detector, and an internal ZELDA wavefront sensor to calibrate non-common path aberrations, assuming that the surface quality of the relay optics of HARMONI satisfy specific requirements. This communication presents (a) the system analysis that was conducted to converge towards these requirement, and the proposed HCM design, (b) an end-to-end simulation tool that has been built to produce realistic datacubes of hour-long observations, and (c) the estimated performance of the HCM, which has been derived by applying differential imaging techniques on the simulated data.

We present the preliminary optical design of METIS, the Mid-infrared E-ELT Imager and Spectrograph, and study the end-to-end performance regarding wavefront errors and non-common path aberrations. We discuss the results of the Monte Carlo simulations that contain the manufacturing and alignment errors of the opto-mechanical system. We elaborate on the wavefront error budget of the instrument detailing all contributors. We investigate the mid and high spatial frequency errors of the optical surfaces, which we model using simulated surface height errors maps of one dimensional Power Spectral Density (PSD) functions.

The Optical Relay Module of the MOSAIC multiple-object spectrograph is used to relay 400-1800nm light picked off from the ELT focal plane to either a fibre-based integral field unit or a natural guide star wavefront sensor. Here we present the preliminary optical design offering a telecentric exit beam with a focal-ratio of F/17.718 and the opto-mechanical analysis of flexures with a study of the impact in the optical layout performances such as: deviation of the PSF centroid, tip-tilt of the image focal plane, variations of the wavefront error, optical quality and pupil wandering at the deformable mirror position.

HIRES is a high-resolution spectrograph to me mounted on one of the Nasmyth foci of the ESO Extremely Large Telescope in Chile. This instrument will be composed by up to four Spectrograph to cover a high spectral range: one for the U band, one for the BVRI band, one for the ZYJH band, and one for the K band. To stabilize and inject the light coming from the telescope into the different spectrographs a Front End will be installed on the Nasmyth focus. In this paper, the design of the HIRES Front End will be presented. It will be composed by a structure, a cable derotator and four benches: two for the Observation mode, one for the Polarimeter arm, and one for the IFU/SCAO. Due to the absence of an interface flange with the telescope the cable derotator will directly support the four benches, positioning them in operation or standby mode. Moreover, due to the different requirements, the cables bundles will be split and derotated in different ways: part of them using different wheels, part of them twisting the cables. For the most critical ones, the electronic will be directly integrated on the derotator system. The preliminary optical and optomechanical design of the observing mode arm will be detailed also showing the techniques used to maximize the modularity of the four sub-Front End modules in order to decrease the Mean Time To Repair and allow for future upgrades or modifications on the single bands.

The GMT-Consortium Large Earth Finder (G-CLEF) will be part of the first generation instrumentation suite for the Giant Magellan Telescope (GMT). G-CLEF is a general purpose echelle spectrograph operating in the optical passband with precision radial velocity (PRV) capability. The measurement precision goal of G-CLEF is 10 cm/sec; necessary for the detection of Earth analogues. This goal imposes challenging stability requirements on the optical mounts and spectrograph support structures especially when considering the instrument’s operational environment. G-CLEF’s accuracy will be influenced by changes in temperature and ambient air pressure, vibration, and micro gravity-vector variations caused by normal telescope motions. For these reasons we have chosen to enclose G-CLEF’s spectrograph in a wellinsulated, vibration-isolated vacuum chamber in a gravity invariant location on GMT’s azimuth platform. Additional design constraints posed by the GMT telescope include; a limited space envelope, a thermal leakage ceiling, and a maximum weight allowance. Other factors, such as manufacturability, serviceability, available technology, and budget are also significant design drivers. G-CLEF will complete its Critical Design phase in mid-2018. In this paper, we discuss the design of GCLEF’s optical mounts and support structures including the choice of a low-CTE carbon-fiber optical bench. We discuss the vacuum chamber and vacuum systems. We discuss the design of G-CLEF’s insulated enclosure and thermal control systems which simultaneously maintain the spectrograph at milli-Kelvin level stability and limit thermal leakage into the telescope dome. Also discussed are micro gravity-vector variations caused by normal telescope slewing, their uncorrected influence on image motion, and how they are dealt with in the design. We discuss G-CLEF’s front-end assembly and fiber-feed system as well as other interface, integration and servicing challenges presented by the telescope, enclosure, and neighboring instrumentation. This work has been supported by the GMTO Corporation, a non-profit organization operated on behalf of an international consortium of universities and institutions: Arizona State University, Astronomy Australia Ltd, the Australian National University, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, the São Paulo Research Foundation, the Smithsonian Institution, the University of Texas at Austin, Texas AM University, the University of Arizona, and the University of Chicago.

We present the optical design of the Red arm (operating at 2-5 µm) of the Planetary Systems Imager (PSI). At the heart of this arm of PSI is a 180x180 silicon lenslet array which will allow diffraction-limited low- resolution integral field spectroscopy over a field of view of 1.5 arcseconds on the Thirty Meter Telescope. The entrance window, lenslet array, and dispersing prisms are the only refractive optics; all other optics are diamond-turned, off-axis, aspherical, gold-coated aluminum and designed with a ‘bolt-and-go’ opto-mechanical approach. We use a homologous material design, meaning we have guaranteed exquisite coefficient of thermal expansion matching which allows us to test, align, and adjust the optics (apart from the lenslet array) in ambient laboratory conditions. Several ‘plug-and-play’ upgrades that increase the scientific capabilities of the instrument are also included in the design such that they can be integrated into the instrument at a later stage without much rework and redesign required. A novel upgrade is an image slicer that sits behind the lenslet array and is illuminated with an insertable fold mirror; this allows us to boost the spectral resolution to 2000-10000 for a field of view of 0.15x0.15 square arcseconds depending on the bandpass. This is a new realm of spectral resolution with ‘large field of view’ IFU instrumentation at these wavelengths and present a novel opportunity for exoplanet characterization. This hybrid lenslet/image slicer combination trades spatial coverage for vastly increased spectral resolution by geometrically rearranging a subset of 23x23 lenslets into a pseudo-slit which is then dispersed using selectable 1st order gratings.

We describe the latest optomechanical design of GMACS, a wide-field, multi-object, moderate-resolution optical spectrograph for the Giant Magellan Telescope (GMT). Specifically, we discuss the details of the structure, mechanisms, optical mounts and deflection tracking/compensation as well as the requirements and considerations used to guide the design. We also discuss GMACS’s interfaces with GMT and other instruments.

We describe the current electronics prototypes for the Flexure Compensation System (FCS) and the Slit Mask Exchange Mechanism (SMEM) for GMACS, a wide-field, multi-object, moderate-resolution optical spectrograph for the Giant Magellan Telescope (GMT). We discuss the details of the FCS and SMEM prototypes, how the prototypes relate to the preliminary conceptual designs of these systems, and what information the prototypes give that can be applied to the final design, as well as the possible next steps for each prototype.

With the imminent launch of the JWST, the field of thermal-infrared (TIR) astronomy will enjoy a revolution. It is easy to imagine that all areas of infrared (IR) astronomy will be greatly advanced, but perhaps impossible to conceive of the new vistas that will be opened. To allow both follow-up JWST observations and a continuance of work started on the ground-based 8m’s, we continue to plan the science cases and instrument design for a TIR imager and spectrometer for early operation on the TMT. We present the current status of our science cases and the instrumentation plans, harnessing expertise across the TMT partnership. This instrument will be proposed by the MICHI team as a second-generation instrument in any upcoming calls for proposals.

The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the Thirty Meter Telescope (TMT). It combines a diffraction limited imager and an integral field spectrograph. This paper focuses on the electrical system of IRIS. With an instrument of the size and complexity of IRIS we face several electrical challenges. Many of the major controllers must be located directly on the cryostat to reduce cable lengths, and others require multiple bulkheads and must pass through a large cable wrap. Cooling and vibration due to the rotation of the instrument are also major challenges. We will present our selection of cables and connectors for both room temperature and cryogenic environments, packaging in the various cabinets and enclosures, and techniques for complex bulkheads including for large detectors at the cryostat wall.

The GMT-Consortium Large Earth Finder (G-CLEF) will be part of the first generation instrumentation suite for the Giant Magellan Telescope (GMT). G-CLEF will be a general purpose optical passband echelle spectrograph with a precision radial velocity (PRV) capability of 10 cm/sec, a requirement necessary for the detection of Earth analogues. The instrument will be particularly sensitive to thermal effects and the necessary stability cannot be achieved through the use of low CTE materials alone. It is the combination of low CTE materials and exquisite thermal control which will enable the instrument to achieve its precision requirements. G-CLEF will complete its Critical Design phase in mid-2018. In this paper, we discuss the precision thermal control systems which enable milli-Kelvin-level stability of the spectrograph and its red and blue focal planes. The measurement electronics and thermal control strategies used in the spectrograph are described. Of particular importance is the development of a continuous LN2 flow cryo-cooler system used to maintain the focal planes at stable cryogenic operational temperatures. This system has been validated with a prototyping effort completed during the instrument’s design phase. We also review G-CLEF’s insulated enclosure which simultaneously maintains the spectrograph a stable temperature and limits the maximum thermal leakage into the telescope dome. This work has been supported by the GMTO Corporation, a non-profit organization operated on behalf of an international consortium of universities and institutions: Arizona State University, Astronomy Australia Ltd, the Australian National University, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, the São Paulo Research Foundation, the Smithsonian Institution, the University of Texas at Austin, Texas AM University, the University of Arizona, and the University of Chicago.

The Mid-infrared E-ELT Imager and Spectrograph (METIS) for the European Extremely Large Telescope (E- ELT) consists of diffraction-limited imagers that cover 3 to 14 microns with medium resolution (R ~ 5000) long slit spectroscopy, and an integral field spectrograph for high spectral resolution spectroscopy (R ~ 100,000) over the L and M bands. We present our approach for high contrast imaging with METIS, covering diffraction suppression with coronagraphs, the removal of residual aberrations using QACITS1, 2 and Phase Sorting Interferometry (PSI),3 and simulations demonstrating the expected contrast.

Following a successful Phase A study, we introduce the delivered conceptual design of the MOSAIC1 multi-object spectrograph for the ESO Extremely Large Telescope (ELT). MOSAIC will provide R~5000 spectroscopy over the full 460-1800 nm range, with three additional high-resolution bands (R~15000) targeting features of particular interest. MOSAIC will combine three operational modes, enabling integrated-light observations of up to 200 sources on the sky (high-multiplex mode) or spectroscopy of 10 spatially-extended fields via deployable integral-field units: MOAO6 assisted high-definition (HDM) and Visible IFUs (VIFU). We will summarise key features of the sub-systems of the design, e.g. the smart tiled focal-plane for target selection and the multi-object adaptive optics used to correct for atmospheric turbulence, and present the next steps toward the construction phase.

We summarize the red channel (2-5 micron) of the Planetary Systems Imager (PSI), a proposed second-generation instrument for the TMT. Cold exoplanets emit the majority of their light in the thermal infrared, which means these exoplanets can be detected at a more modest contrast than at other wavelengths. PSI-Red will be able to detect and characterize a wide variety of exoplanets, including radial-velocity planets on wide orbits, accreting protoplanets in nearby star-forming regions, and reflected-light planets around the nearest stars. PSI-Red will feature an imager, a low-resolution lenslet integral field spectrograph, a medium-resolution lenslet+slicer integral field spectrograph, and a fiber-fed high-resolution spectrograph.

MANIFEST is a multi-object fibre facility for the Giant Magellan Telescope that uses ‘Starbug’ robots to accurately position fibre units across the telescope’s focal plane. MANIFEST, when coupled to the telescope’s planned seeinglimited instruments, offers access to larger fields of view; higher multiplex gains; versatile focal plane reformatting of the focal plane via integral-field-units; image-slicers; and in some cases higher spatial and spectral resolution. The TAIPAN instrument on the UK Schmidt Telescope is now close to science verification which will demonstrate the feasibility of the Starbug concept. We are now moving into the conceptual development phase for MANIFEST, with a focus on developing interfaces for the telescope and for the instruments.

The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the Thirty Meter Telescope (TMT) that will be used to sample the corrected adaptive optics field by NFIRAOS with a near-infrared (0.8 - 2.4 µm) imaging camera and Integral Field Spectrograph (IFS). In order to understand the science case specifications of the IRIS instrument, we use the IRIS data simulator to characterize photometric precision and accuracy of the IRIS imager. We present the results of investigation into the effects of potential ghosting in the IRIS optical design. Each source in the IRIS imager field of view results in ghost images on the detector from IRIS’s wedge filters, entrance window, and Atmospheric Dispersion Corrector (ADC) prism. We incorporated each of these ghosts into the IRIS simulator by simulating an appropriate magnitude point source at a specified pixel distance, and for the case of the extended ghosts redistributing flux evenly over the area specified by IRIS’s optical design. We simulate the ghosting impact on the photometric capabilities, and found that ghosts generally contribute negligible effects on the flux counts for point sources except for extreme cases where ghosts coalign with a star of ▵m>2 fainter than the ghost source. Lastly, we explore the photometric precision and accuracy for single sources and crowded field photometry on the IRIS imager.

The current status of IRIS imager at NAOJ is reported. IRIS (Infrared Imaging Spectrograph) is a first light instrument of TMT (Thirty Meter Telescope). IRIS has just passed the preliminary design review and moved forward to the final design phase. In this paper, optical and mechanical design of IRIS imager and prototyping activities conducted during the preliminary design phase are summarized.

HARMONI (High Angular Resolution MOnolithic Integral field spectrograph)¹ is a planned first-light integral field spectrograph for the Extremely Large Telescope. The spectrograph sub-system is being designed, developed, and built by the University of Oxford. The project has just completed the Preliminary Design Review (PDR), with all major systems having nearly reached a final conceptual design. As part of the overall prototyping and assembly, integration, and testing (AIT) of the HARMONI spectrograph, we will be building a full-scale engineering model of the spectrograph. This will include all of the moving and mechanical systems, but without optics. Its main purpose is to confirm the AIT tasks before the availability of the optics, and the system will be tested at HARMONI cryogenic temperatures. By the time of the construction of the engineering model, all of the individual modules and mechanisms of the spectrograph will have been prototyped and cryogenically tested. The lessons learned from the engineering model will then be fed back into the overall design of the spectrograph modules ahead of their development.

This paper discusses refractive, reflective and catadioptric designs for the Thirty Meter Telescope Fiber Wide Field Optical Spectrograph (WFOS) instrument concept. Custom macros were written to evaluate performance at the detector plane with the grating at the pupil as a function of fiber position in the pseudo-slit and wavelength, and a tolerance analysis has been performed for each design based on best engineering practices to assess performance robustness against opto-mechanical errors. The catadioptric camera appears to provide the best compromise in this regard.