- Front Matter: Volume 9149
- Archive Operations and Data Flow
- Time Domain Follow-up I
- Time Domain Follow-up II
- Operations Benchmarking and Metrics
- Program and Observation Scheduling
- Science Operations I
- Science Operations II
- Operations and Data Quality Control
- User Support
- Site and Facility Operations I
- Site and Facility Operations II
- Site and Facility Operations III
- Posters: Thursday
The Space Surveillance Telescope (SST) is a three-mirror Mersenne-Schmidt telescope with a 3.5 m primary mirror that is designed for deep, wide-area sky surveys. The SST design incorporates a camera with charge-coupled devices (CCDs) on a curved substrate to match the telescope’s inherent field curvature, capturing a large field-of-view (6 square degree) with good optical performance across the focal surface. The unique design enables a compact mount construction for agile pointing, contributing to survey efficiency. However, the optical properties make the focus and alignment challenging due to an inherently small depth of focus and the additional degrees of freedom that result from having a powered tertiary mirror. Adding to the challenge, the optical focus and alignment of the mirrors must be accomplished without a dedicated wavefront sensor.
Procedures created or adapted for use at the SST have enabled a successful campaign for focus and alignment, based on a five-step iterative process to (1) position the tertiary mirror along the optical axis to reduce defocus; (2) reduce spherical aberration by a coordinate move of the tertiary and secondary mirrors; (3) measure the higher order aberrations including astigmatism and coma; (4) associate the measured aberrations with the predictions of optical ray-tracing analysis; and (5) apply the mirror corrections and repeat steps 1-4 until optimal performance is achieved (Woods et al. 2013). A set of predicted mirror motions are used to maintain system performance across changes in telescope elevation pointing and in temperature conditions, both nightly and seasonally. This paper will provide an overview of the alignment procedure developed for the SST and will report on the focus performance through the telescope’s second year, including lessons learned over the course of operation.
The Canada France Hawaii Telescope operates a 3.6m Optical/Infrared telescope on the summit of Mauna Kea. As an effort to improve delivered image quality in a cost-effective manner, a dome venting project was initiated to eliminate local contributions to 'seeing' that exist along the optical path and arise to a large extent due to temperature gradients throughout the dome volume.
The quality of images delivered by the telescope is adversely affected by variations in air temperature within the telescope dome. Air temperature differences are caused by the air’s contact with large structures. They are different from ambient as a result of their large thermal inertias and the consequent inability of these structures to follow rapid air temperature changes.
The dome venting project is an effort to add a series of large openings, “vents”, in the skin of the dome with the purpose of allowing free stream summit winds to flush out “stagnant air”. The term, “stagnant air”, applies to thermally mixed air from the inside of the dome environment that, for one reason or another, has been heated or cooled by surfaces in the dome environment.
The addition of vents to the CFHT dome is intended to facilitate the passive flushing of interior air by the local wind, thereby greatly reducing air temperature variations, a process that has been successfully demonstrated to improve image quality at other telescope facilities and supported by recent water tunnel tests conducted by CFHT staff.
The NOAO Data Lab will allow users to efficiently utilize catalogs of billions of objects, augment traditional telescope imaging and spectral data with external archive holdings, publish high level data products of their research, share custom results with collaborators and experiment with analysis toolkits. The goal of the Data Lab is to provide a common framework and workspace for science collaborations and individuals to use and disseminate data from large surveys.
In this paper we describe the motivations behind the NOAO Data Lab and present a conceptual overview of the activities we plan to support. Specific science cases will be used to develop a prototype framework and tools, allowing us to work directly with scientists from survey teams to ensure development will remain focused on scientifically productive tasks. This will additionally develop a pool of both scientific and technical experts who can provide ongoing advice and support for community users as the scope and capabilities of the Data Lab expand.
The High Energy Stereoscopic System (H.E.S.S.) in Namibia measures gamma-ray emission via the detection of Cherenkov light in the optical waveband and is therefore highly sensitive to changes in the transparency of the atmosphere. This is especially true for aerosols, small dust particles covering the sky at the H.E.S.S. site and severely reducing the atmospheric transparency for blue Cherenkov light for several days each year.
To quantify this effect, the Cherenkov Transparency Coefficient has been introduced as a hardware-independent parameter, which enables a correction of measured gamma-ray brightnesses.
Neighbouring the Cherenkov array, the Automated Telescope for Optical Monitoring (ATOM) operates an all-sky cloud camera as secondary instrument. Due to its high exposure frequency, the cloud camera may act as a detection system, if image parameters indicating low Cherenkov transparency are identified. However, the current instrument – originally conceived as a weather warning system – only produces white-light frames in low resolution. This study examines all frames taken with the current instrument since 2008 which coincide with H.E.S.S. observations in order to characterise relations with the measured Cherenkov transparency.
As a result of this preliminary study, trivial relations between the examined sky monitor observations and gamma-ray brightness can be excluded. However, it is planned to expand the scope of this activity with an upgraded device by introducing colour dependency and more advanced photometry with a larger number of objects in the near future.
The Automatic Telescope for Optical Monitoring (ATOM) is a 75 cm Ritchey-Chrétien telescope situated in Göllschau, Namibia, which forms part of the High Energy Stereoscopic System (H.E.S.S.). This paper presents ANDAQ, which allows to step from robotic to fully automatic observation by eliminating the need for daily human interaction. The main module responsible for the telescope operation forms a newly developed observer program, which also includes control of the telescope enclosure and offers various other tasks, like automated flat-fielding with live-analysis.
ANDAQ features its own TCP server for outside communication, making it possible to insert commands during the night. It possesses various means of monitoring internal and environmental parameters, and adjusts observation if necessary. This paper includes an description of the all-sky camera serving as cloud detector, supplemented by an additional rain detection device, and shows how operation is stopped as soon as weather parameters are below a defined standard, and automatically restarted once conditions recover. ANDAQ possesses a modular design based on a management core which starts and stops components as needed. This eases introduction of further functionality considerably and current development efforts include closer links to the main H.E.S.S. operation as well as live-analysis of exposures, allowing repeated observation in case of increased activity of a source.
ANDAQ has undergone extensive testing and has not seen any major problems so far. It may thus well serve as base for a future automated monitoring programme for the Cherenkov Telescope Array.