The Rapid Prototyping Array (RPA) is a toy radio telescope located 30 miles from U. C. Berkeley in Lafayette, CA. It serves primarily as a software development test bed for the Allen Telescope Array (ATA). We have developed a minimally functional prototype of the ATA control system founded on C++, Java, and a CORBA-based distributed architecture. The system controls RPA pointing, electronics, and data processing, culminating in a real-time software correlator (i.e. an imaging system). This system has helped us characterize our preliminary design of the ATA control system. Overall, the distributed architecture provided successful, versatile control supporting a wide range of experiments from satellite tracking to beam characterization to celestial observation. However, some weaknesses in the CORBA communications layer were identified, and the synergies of mixing C++ and Java were balanced by paradigm mismatch between the languages. We learned that Java was as fast as C++ and supported more ready-made libraries. Based on these experiences, we changed our design to eliminate CORBA and build a pure Java system at the ATA, which is now under development.

The software designed to monitor and control the Robert C. Byrd Green Bank Telescope (GBT) was generalized into Ygor, an object oriented framework for control system implementation. Ygor is deployed on the GBT on a variety of platforms, together making up the GBT Monitor and Control system. The design of the Ygor system will be presented along with the design philosophy leading to these design decisions. Implementation details and case studies will be used to illustrate the advantages of this system.

The National Solar Observatory is nearing completion of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) project. SOLIS will replace the existing capabilities of the Vacuum Telescope on Kitt Peak near Tucson, Arizona and will provide new scientific capabilities over its expected 25 year life-time. The evolution of the Common Object Request Broker Architecture (CORBA) and the availability of compliant Object Request Brokers (ORBs) and Common Object Services (COS) facilitates the development of cross-platform, multi-language software systems that are reliable and flexible. The SOLIS Communications System employs three ORBs, a naming service and a notification service to support the project's core distributed and real-time control systems that are written primarily in Java or C++ for the Linux, Solaris and VxWorks operating systems. One particularly useful aspect of the communications system is the ease of event monitoring demonstrated by the development of tools such as a logging service and a generic instrument control graphical user interface.

A telescope system is composed of a set of real-world objects that are mapped onto software objects whose properties are described in XML configuration files. These XML files are processed to automatically generate user interfaces, underlying communication mechanisms, and extendible source code. Developers need not write user interfaces or communication methods but can focus on the production of scientific results. Any modifications or additions of objects can be easily achieved by editing or generating corresponding XML files and compiling them into the system. This framework can be utilized to implement servo controllers, device drivers, observing algorithms and instrument controllers; and is applicable to any problem domain that requires a user-based interaction with the inputs and outputs of a particular resource or program. This includes telescope systems, instruments, data reduction methods, and database interfaces. The system is implemented using Java, C++, and CORBA.

The Atacama Large Millimeter Array (ALMA) is a joint project between astronomical organizations in Europe and North America. ALMA will consist of at least 64 12-meter antennas operating in the millimeter and sub-millimeter range, with baselines up to 14 km. It will be located at an altitude above 5000m in the Chilean Atacama desert. The ALMA Common Software (ACS) provides a software infrastructure common to all partners and consists of a documented collection of common patterns and of components that implement those patterns. The heart of ACS is an object model based on Distributed Objects (DOs), implemented as CORBA objects. The teams responsible for the control system development use DOs as the basis for components and devices such as an antenna mount control. ACS provides common CORBA-based services such as logging, error and alarm management, configuration database and lifecycle management. A code generator creates a Java Bean for each DO. Programmers can write Java client applications by connecting those Beans with data-manipulation and visualization Beans. ACS is based on the experience gained in the astronomical and particle accelerator domains, and reuses and extends proven concepts and components. Although designed for ALMA, ACS can be used in other new control systems, since it implements proven design patterns using state of the art, stable and reliable technology. This paper presents the architecture of ACS and its status, detailing the object model and major services.

The Atacama Large Millimeter Array (ALMA) is a joint project involving astronomical organizations in Europe and North America. ALMA will consist of at least 64 12-meter antennas operating in the millimeter and sub-millimeter range. It will be located at an altitude of about 5000m in the Chilean Atacama desert. The primary challenge to the development of the software architecture is the fact that both its development and runtime environments will be distributed. Groups at different institutes will develop the key elements such as Proposal Preparation tools, Instrument operation, On-line calibration and reduction, and Archiving. The Proposal Preparation software will be used primarily at scientists' home institutions (or on their laptops), while Instrument Operations will execute on a set of networked computers at the ALMA Operations Support Facility. The ALMA Science Archive, itself to be replicated at several sites, will serve astronomers worldwide. Building upon the existing ALMA Common Software (ACS), the system architects will prepare a robust framework that will use XML-encoded entity objects to provide an effective solution to the persistence needs of this system, while remaining largely independent of any underlying DBMS technology. Independence of distributed subsystems will be facilitated by an XML- and CORBA-based pass-by-value mechanism for exchange of objects. Proof of concept (as well as a guide to subsystem developers) will come from a prototype whose details will be presented.

Traditionally, instrument command and control systems have been developed specifically for a single instrument. Such solutions are frequently expensive and are inflexible to support the next instrument development effort. NASA Goddard Space Flight Center is developing an extensible framework, known as Instrument Remote Control (IRC) that applies to any kind of instrument that can be controlled by a computer. IRC combines the platform independent processing capabilities of Java with the power of the Extensible Markup Language (XML). A key aspect of the architecture is software that is driven by an instrument description, written using the Instrument Markup Language (IML). IML is an XML dialect used to describe graphical user interfaces to control and monitor the instrument, command sets and command formats, data streams, communication mechanisms, and data processing algorithms. The IRC framework provides the ability to communicate to components anywhere on a network using the JXTA protocol for dynamic discovery of distributed components. JXTA (see http://www.jxta.org) is a generalized protocol that allows any devices connected by a network to communicate in a peer-to-peer manner. IRC uses JXTA to advertise a device?s IML and discover devices of interest on the network. Devices can join or leave the network and thus join or leave the instrument control environment of IRC. Currently, several astronomical instruments are working with the IRC development team to develop custom components for IRC to control their instruments. These instruments include: High resolution Airborne Wideband Camera (HAWC), a first light instrument for the Stratospheric Observatory for Infrared Astronomy (SOFIA); Submillimeter And Far Infrared Experiment (SAFIRE), a principal investigator instrument for SOFIA; and Fabry-Perot Interferometer Bolometer Research Experiment (FIBRE), a prototype of the SAFIRE instrument, used at the Caltech Submillimeter Observatory (CSO). Most recently, we have been working with the Submillimetre High Angular Resolution Camera IInd Generation (SHARCII) at the CSO to investigate using IRC capabilities with the SHARC instrument.

OmegaCAM is a wide field optical imager that is expected to start its operations towards the end of 2003, at the VLT Survey Telescope (VST), part of the VLT Observatory, operated in Paranal (Chile) by the European Southern Observatory (ESO). OmegaCAM will almost completely fill VST one squared degree field of view with a CCD imaging mosaic 16k x 16k pixels in size. In addition to the scientific array, four auxiliary CCDs will be used for autoguiding and image analysis. Despite its conceptual simplicity and due to the large size of the CCD mosaic, OmegaCAM posed several challenges in the design of its mechanics, electronics, cryogenics and software. In this paper we report on the design of the OmegaCAM Instrument Software (INS), which is in charge of the control and operations of the instrument. We first introduce the instrument control system characteristics and the INS software development process. We then describe the main characteristics of the INS subsystems in charge of instrument functions control, autoguiding, image analysis and operations coordination. Finally, we discuss the performances expected from the software in the acquisition and storage of the large amount of data that will come from the scientific array.

After having established routine science operations for four 8 m single dish telescopes and their first set of instruments at the Paranal Observatory, the next big engineering challenge for ESO has been the VLT Interferometer. Following an intense integration period at Paranal, first fringes were obtained in the course of last year, first with two smaller test siderostats and later with two 8 m VLT telescopes. Even though optical interferometry today may be considered more experimental than single telescope astronomy, we have aimed at developing a system with the same requirements on reliability and operability as for a single VLT telescope. The VLTI control system is responsible for controlling and co-ordinating all devices making up VLTI, where a telescope is just one out of many subsystems. Thus the pure size of the complete system increases the complexity and likelihood of failure. Secondly, some of the new subsystems introduced, in particular the delay lines and the associated fringe-tracking loop, have more demanding requirements in terms of control loop bandwidth, computing power and communication. We have developed an innovative generic multiprocessor controller within the VLT framework to address these requirements. Finally, we have decided to use the VLT science operation model, whereby the observation is driven by observation blocks with minimum human real-time interaction, which implies that VLTI is seen as one machine and not as a set of telescopes and other subsystems by the astronomical instrument. In this paper we describe the as-built architecture of the VLTI control and data flow system, emphasising how new techniques have been incorporated, while at the same time the investments in technology and know-how obtained during the VLT years have been protected. The result has been a faster development cycle, a robustness approaching that of VLT single dish telescopes and a "look and feel" identical to all other ESO observing facilities. We present operation, performance and development cost data to confirm this. Finally we discuss the plans for the coming years, when more and more subsystems will be added in order to explore the full potential of the VLTI.

The Keck Interferometer links the two 10m Keck Telescopes located atop Mauna Kea in Hawaii. It is the first 10m class, fully AO equipped interferometer to enter operation. Further, it is the first large interferometer designed to be handed over from a design and implementation team to a separate operations team, and be used by astronomers who are not interferometer specialists. As such it offers unique challenges in reducing an extremely complex and powerful system to an apparently simple user interface, and providing a well engineered system that can be maintained by people who did not develop it. This paper gives an overview of the control system that has been implemented for the single baseline operation of the instrument, and indicates how this will be extended to allow control of the future modes of the instrument (nulling, differential phase and astrometry). The control system has several parts. One is for control of "slow" sub-systems, which is based in the EPICS architecture, already ubiquitous at the Keck Observatory. Another, used to control hard real time sub-systems, is based on a new infrastructure developed at JPL, programmed in C++, Java, and using CORBA for communication. This infrastructure has been developed specifically with the problems of interferometric control in mind and is used in JPL's flight testbeds as well as the Keck Interferometer. Finally, a user interface and high level control layer is in development using a variety of tools including UML based modeling in the Rhapsody tool (using C++ and CORBA), Java, and Tcl/Tk for prototyping.

The 'Internet boom' of the past few years has spurred the development of a number of technologies to provide services such as secure communications, reliable messaging, information publishing and application distribution for commercial applications. Over the same period, a new generation of computer languages have also developed to provide object oriented design and development, improved reliability, and cross platform compatibility. Whilst the business models of the 'dot.com' era proved to be largely unviable, the technologies that they were based upon have survived and have matured to the point were they can now be utilized to build secure, robust and complete observatory control control systems. This paper will describe how Electro Optic Systems has utilized these technologies in the development of its third generation Robotic Observatory Control System (ROCS). ROCS provides an extremely flexible configuration capability within a control system structure to provide truly autonomous robotic observatory operation including observation scheduling. ROCS was built using Internet technologies such as Java, Java Messaging Service (JMS), Lightweight Directory Access Protocol (LDAP), Secure Sockets Layer (SSL), eXtendible Markup Language (XML), Hypertext Transport Protocol (HTTP) and Java WebStart. ROCS was designed to be capable of controlling all aspects of an observatory and be able to be reconfigured to handle changing equipment configurations or user requirements without the need for an expert computer programmer. ROCS consists of many small components, each designed to perform a specific task, with the configuration of the system specified using a simple meta language. The use of small components facilitates testing and makes it possible to prove that the system is correct.

Telescopes capable of making observing decisions independent of human supervision have become a reality in the 21st century. These new telescopes are likely to replace automated systems as the telescopes of choice. A fully robotic implementation offers not only reduced operating costs, but also significant gains in scientific output over automated or remotely operated systems. The design goals are to maximise the telescope operating time and minimise the cost of diagnosis and repair. However, the demands of a robotic telescope greatly exceed those of its remotely operated counterpart, and the design of the computing system is key to its operational performance. This paper outlines the challenges facing the designer of these computing systems, and describes some of the principles of design which may be applied. Issues considered include automatic control and efficiency, system awareness, robustness and reliability, access, security and safety, as well as ease-of-use and maintenance. These requirements cannot be considered simply within the context of the application software. Hence, this paper takes into account operating system, hardware and environmental issues. Consideration is also given to accommodating different levels of manual control within robotic telescopes, as well as methods of accessing and overriding the system in the event of failure.

NGST ground software and flight software will enable exciting scientific research programs that will address fundamental questions about the structure of the universe and the evolution of galaxies, stars and planets. The design of the spacecraft and instrument command system architecture acknowledges from project start that the ground software and flight software are parts of a single integrated system. A layered architecture is presented where the ground system software provides descriptions of "what to do" with the spacecraft and science instruments, while the flight software provides the detailed "how to do" rules required to execute these requests. All specific knowledge about onboard computer memory structures, hardware device communication rules, and spacecraft/science instrument operational sequences will be encapsulated onboard the spacecraft. The ground system will simply supply high-level alphanumeric requests that the flight software knows how to interpret and perform.

We examine the factors that drive the size and cost of software for a hypothetical 30 meter telescope and compare those to that of a hypothetical 10 meter telescope. Our goal is to explore methods for developing estimates for such costs. The estimates provided here are intended primarily as examples for these methods, and should not be construed as accurate.

The Franco-Italian VIMOS instrument is a VIsible imaging Multi-Object Spectrograph with outstanding multiplex capabilities, allowing to take spectra of more than 800 objects simultaneously, or integral field spectroscopy mode in a 54x54 arcsec area. VIMOS is being installed at the Nasmyth focus of the third Unit Telescope of the European Southern Observatory Very Large Telescope (VLT) at Mount Paranal in Chile. This paper will describe the analysis, the design and the implementation of the VIMOS Instrument Control System, using UML notation. Our Control group followed an Object Oriented software process while keeping in mind the ESO VLT standard control concepts. At ESO VLT a complete software library is available. Rather than applying waterfall lifecycle, ICS project used iterative development, a lifecycle consisting of several iterations. Each iteration consisted in : capture and evaluate the requirements, visual modeling for analysis and design, implementation, test, and deployment. Depending of the project phases, iterations focused more or less on specific activity. The result is an object model (the design model), including use-case realizations. An implementation view and a deployment view complement this product. An extract of VIMOS ICS UML model will be presented and some implementation, integration and test issues will be discussed.

The Jet Propulsion Laboratory (JPL) has built several optical interferometers using a common software framework developed for this purpose. The heart of this framework is the Realtime Control (RTC) software product. RTC has evolved from its initial implementation to include a powerful dynamic configuration capability and to use Common Object Request Broker Architecture (CORBA) technology for commanding and telemetry. This paper describes the current implementation of this toolkit.

Efficient operation of a submillimeter interferometer requires remote (preferably automated) control of mechanically tuned local oscillators, phase-lock loops, mixers, optics, calibration vanes and cryostats. The present control system for these aspects of the Submillimeter Array (SMA) will be described. Distributed processing forms the underlying architecture. In each antenna cabin, a serial network of up to ten independent 80C196 microcontroller boards attaches to the real-time PowerPC computer (running LynxOS). A multi-threaded, gcc-compiled program on the PowerPC accepts top-level requests via remote procedure calls (RPC), subsequently dispatches tuning commands to the relevant microcontrollers, and regularly reports the system status to optical-fiber-based reflective memory for common access by the telescope monitor and error reporting system. All serial communication occurs asynchronously via encoded, variable-length packets. The microcontrollers respond to the requested commands and queries by accessing non-volatile, rewriteable lookup-tables (when appropriate) and executing embedded software that operates additional electronic devices (DACs, ADCs, etc.). Since various receiver hardware components require linear or rotary motion, each microcontroller also implements a position servo via a one-millisecond interrupt service routine which drives a DC-motor/encoder combination that remains standard across each subsystem.

Ultracam is a high speed, three channel CCD camera designed to provide imaging photometry at high temporal resolution, allowing the study of rapidly changing astronomical phenomena such as eclipses, rapidly flickering light curves and occultation events. It is designed to provide frame rates up to 500 Hz with minimum inter-frame dead time and to time-tag each frame to within 1 millisecond of UT. The high data rates that this instrument produces, together with its use as a visitor instrument at a number of observatories, have lead to a highly modular design. Each major service (camera, control, sequencing, data handlers, etc.) is a separate process that communicates using XML documents via HTTP transport, allowing the services to be redeployed or reconfigured with minimal effort. The use of XML and HTTP also allows a web browser to act as a front end for any of the services, as well as providing easy access to services from other control systems. The overall design allows for simple re-engineering for a variety of imaging systems, and is already expected to provide control of IR arrays for the UKIRT Wide-Field Camera project. The instrument has been successfully commissioned on the William Herschel Telescope.

The SOAR Telescope is in the final phases of construction. Software development is progressing well, in accordance with installation of the telescope subsystems. Our original strategy, explored during the prototype phase, has been maintained and improved, resulting in a software package of great flexibility. This paper describes the implementation details that have proved to be most useful for the development of the SOAR TCS.

The software development for an upgrade to the Hobby-Eberly Telescope (HET) was done in LabVIEW. In order to improve the performance of the HET at the McDonald Observatory, a closed-loop system had to be implemented to keep the mirror segments aligned during periods of observation. The control system, called the Segment Alignment Maintenance System (SAMS), utilized inductive sensors to measure the relative motions of the mirror segments. Software was developed in LabVIEW to tie the sensors, operator interface, and mirror-control motors together. Developing the software in LabVIEW allowed the system to be flexible, understandable, and able to be modified by the end users. Since LabVIEW is built using block diagrams, the software naturally followed the designed control system's block and flow diagrams, and individual software blocks could be easily verified. LabVIEW's many built-in display routines allowed easy visualization of diagnostic and health-monitoring data during testing. Also, since LabVIEW is a multi-platform software package, different programmers could develop the code remotely on various types of machines. LabVIEW's ease of use facilitated rapid prototyping and field-testing. There were some unanticipated difficulties in the software development, but the use of LabVIEW as the software "language" for the development of SAMS contributed to the overall success of the project.

This paper describes how the Tcl scripting language and C API has been used as the software environment for a telescope pointing kernel so that new pointing algorithms and software architectures can be developed and tested without needing a real-time operating system or real-time software environment. It has enabled development to continue outside the framework of a specific telescope project while continuing to build a system that is sufficiently complete to be capable of controlling real hardware but expending minimum effort on replacing the services that would normally by provided by a real-time software environment. Tcl is used as a scripting language for configuring the system at startup and then as the command interface for controlling the running system; the Tcl C language API is used to provided a system independent interface to file and socket I/O and other operating system services. The pointing algorithms themselves are implemented as a set of C++ objects calling C library functions that implement the algorithms described in [2]. Although originally designed as a test and development environment, the system, running as a soft real-time process on Linux, has been used to test the SOAR mount control system and will be used as the pointing kernel of the SOAR telescope control system

This paper describes the design and implementation of the Next Generation Telescope Control System (NGTCS). It outlines the requirements of a generic telescope control system and presents an architectural solution to the requirements problem, and an implementation in Java. The modular design of the NGTCS enables a TCS application to be developed for virtually any telescope using the NGTCS core system, and developing Java classes for system-specific functionality. The Liverpool Telescope will use a TCS built with the NGTCS software.

The Joint Astronomy Centre (JAC) operates the James Clerk Maxwell Telescope (JCMT), the world's largest sub-mm telescope, and the United Kingdom Infrared Telescope (UKIRT), the world's largest telescope dedicated solely to infrared astronomy. Although these two telescopes investigate different regions of the electro-magnetic spectrum and have different mounting arrangements, the JAC (in collaboration with the Anglo-Australian Observatory) has developed the Portable Telescope Control System (PTCS) software so that it can be used on both JAC telescopes. The benefit of this work is increased efficiency, reduced maintenance time, and reduced personnel costs as a result of using a common code base on both JAC telescopes. During the next year, the PTCS will be enhanced as part of the JCMT Observatory Control System (OCS) project so that configuration information can be transmitted to the PTCS via XML files. This will simplify the PTCS interface and expedite the implementation of the OCS. This paper gives an overview of the PTCS, describes its use on both telescopes, and indicates how XML files will be used to configure the telescope prior to the start of an observation.

The JCMT, the world's largest sub-mm telescope, has had essentially the same VAX/VMS based control system since it was commissioned. For the next generation of instrumentation we are implementing a new Unix/VxWorks based system, based on the successful ORAC system that was recently released on UKIRT. The system is now entering the integration and testing phase. This paper gives a broad overview of the system architecture and includes some discussion on the choices made. (Other papers in this conference cover some areas in more detail). The basic philosophy is to control the sub-systems with a small and simple set of commands, but passing detailed XML configuration descriptions along with the commands to give the flexibility required. The XML files can be passed between various layers in the system without interpretation, and so simplify the design enormously. This has all been made possible by the adoption of an Observation Preparation Tool, which essentially serves as an intelligent XML editor.

The SOAR Telescope Project has developed a highly integrated Telescope and Observatory Control System, written in the LabVIEW graphical "G" language. A "plug-in" architecture and the ease of developing GUIs in LabVIEW has lead to a design and implementation that gives the operators flexibility, ease of use and a clear visual insight into the complex interactions of the many subsystems of a modern telescope. Care has been taken to abstract the many complexities into displays and controls that allows the operators to concentrate more on the functional operation of the telescope and observatory, and less on the intricacies of the various subsystems hardware. The User Interface includes many innovative features to make the operator?s job easier. Our process methodology for developing the TCS/OCS and continuous peer review/revision are enabling us to exceed SOAR's requirements and create a TCS/OCS that can easily be applied to other telescopes.

Testbeds and production systems need lightweight, capable, and rapidly developed applications. We have developed several such scripts for testing and operating the Keck Interferometer. Two stand-alone (Tcl/Tk script) applications implemented to support the Keck Interferometer are discussed. The first is a front end to automatic and manual optical alignment embedded software, developed using the Keck Observatory Keyword API extension. The second is a user interface to the Interferometer Sequencer that communicates with it via both Keywords and Common Orbject Request Broker Architecture (CORBA). We discuss client-side CORBA scripts implemented in Tcl, Perl and Python. These are all technologies that are either currently being used on testbeds at JPL or being evaluated for future use. Finally, a Python example demonstrating implementation of a simple CORBA server is presented.

The NRAO-Green Bank Telescope, the world's largest, fully steerable radio telescope, is now in routine use by visiting astronomers. The telescope is unique because of its offset optical design and its complex suite of state-of-the-art instruments. To exploit the full powers of the system, observers and staff members require intuitive user interfaces. We will demonstrate one of the various graphical user interfaces that have been built for the telescope. The interface, written in Tcl/Tk and used predominately by staff engineers, telescope operators, and programmers, is designed for very detailed monitoring and debugging of telescope components. The interface lies on top of an object-oriented control system that provides the GUI builder a set of software methods that is the same for every GBT device, from receivers to detectors. The uniform set of methods reduces the work normally needed in creating a high-level user interface and allows for the creation of interfaces in a range of programming languages.

The SOLIS solar telescope collects data at a high rate, resulting in 500 GB of raw data each day. The SOLIS Data Handling System (DHS) has been designed to quickly process this data down to 156 GB of reduced data. The DHS design uses pools of distributed reduction processes that are allocated to different observations as needed. A farm of 10 dual-cpu Linux boxes contains the pools of reduction processes. Control is through CORBA and data is stored on a fibre channel storage area network (SAN). Three other Linux boxes are responsible for pulling data from the instruments using SAN-based ringbuffers. Control applications are Java-based while the reduction processes are written in C++. This paper presents the overall design of the SOLIS DHS and provides details on the approach used to control the pooled reduction processes. The various strategies used to manage the high data rates are also covered.

Nowadays, computer clusters offer the best price/performance ratio for a huge range of scientific and industrial applications. Among the various cluster architectures so far proposed, the most promising surely is the Beowulf: a distributed computational system formed by a server plus one or more client nodes connected to the server through a fast communication network. A Beowulf computer class looks like the most promising solution to cope with the processing of the enormous amount of data produced by the present and, even more, planned Wide Field Telescopes. Indeed Wide Field cameras are built as CCD mosaic and the nature embarrassingly parallel of such data make a parallel machine particularly suitable to process them as most of the data process can be execute independently on each CCD of the mosaic. A Beowulf cluster of one master plus eight nodes has been installed at the Astronomical Observatory of Naples. We will present results on tests performed on various hardware configurations in order to find the cluster configuration optimized, in terms of performance, for the specific application of reducing Wide Field images. A comparison with other hardware platform will also be presented.

This paper describes tools and methods used to manage DEIMOS removable elements (filters, gratings, and slitmasks). The iterative process of adapting and refining our basic strategy to the working conditions and requirements of Keck Observatory staff is not yet complete; hence this paper should be read as a Work In Progress report.

A typical modern telescope control system points by first calculating the direction of the target in nominal mount coordinates and then applying small corrections to the demanded mount angles. The pointing refers to the rotation axis of the instrument mount, and rotator demands are calculated via parallactic angle. This simple approach works well enough when the corrections are small and the accuracy objectives are modest. However, a more rigorous approach can pay off, in the form of improved pointing, more accurate guide probe predictions, reduced residual field rotation and reliable world coordinate system information even when the detector is off-axis. In this paper I propose a rigorous vector/matrix algorithm for generating pointing predictions on an imperfect telescope, with support for autoguiding, field stabilization and world coordinate systems even in difficult cases such as Nasmyth and coude.

The POrtable Submillimeter Telescope (POST) was put into operation in Nov. 1999. In this paper, we briefly introduce the control system of the telescope, including both hardware and software. The hardware is based on the S-Bus of a SUN workstation. Industrial standard I/O interfaces are adopted to fulfil different purposes of information transfer. Pulse width modulation (PWM) and harmonic driver are adopted to the antenna driving system, which is controlled in a mode of closed-loop positional feedback. The control software is to accomplish various observing and diagnostic functions of the telescope. The software is designed as a centralized real-time, multi-task package on the base of the UNIX platform. Present version of the entire control software includes 14,000 lines of source code in C language. The control system as a whole realizes all functions of a highly automatic all-sky submillimeter telescope used to observe cosmic submillimeter line radiation, particularly the neutral atomic carbon line at 492GHz. Besides, the system can be operated remotely. The principle as well as the software can be applied to control other precision radio telescopes.

We review a variety off-the-shelf single board computers being considered for application in the Allen Telescope Array (ATA) for antenna control. The evaluation process used the following procedure: we developed an equivalent small program on each computer. This program communicates over a local area network (Ethernet) to a remote host, and makes some simple tests of the network bandwidth. The controllers are evaluated according to 1) the measured performance and 2) the time it takes to develop the software. Based on these tests we rate each controller and choose one based on the Ajile aJ-100 processor for application at the ATA.

Star image tracking in the LLMC is composed of two direction movements, that is, a horizontal tracking of the CCD chip (camera) and a vertical tracking of the telescope tube in the zenith distance. Based on an idea that the two tracking control systems should be incorporate. A new hardware structure of tracking control system in the LLMC is presented in this paper. The system can simultaneously output two gates of motor driving pulses, one for the CCD tracking in horizontal direction and another for the tube tracking in vertical direction or for the slow motion placement of the tube in vertical direction. Experiments indicate that the driving pulses output from the new system can be controlled more easily than those from old systems in software mode and its frequency can be higher. The programming methods for the ASM control program in the micro-controller system and for the C++ control program in the host PC are described. Some primary results and experiences from the experiments are also presented in the last.

The photometric telescope (PT) provides observations necessary for the photometric calibration of the Sloan Digital Sky Survey (SDSS). Because the attention of the observing staff is occupied by the operation of the 2.5 meter telescope which takes the survey data proper, the PT must reliably take data with little supervision. In this paper we describe the PT's observing program, MOP, which automates most tasks necessary for observing. MOP's automated target selection is closely modeled on the actions a human observer might take, and is built upon a user interface that can be (and has been) used for manual operation. This results in an interface that makes it easy for an observer to track the activities of the automating procedures and intervene with minimum disturbance when necessary. MOP selects targets from the same list of standard star and calibration fields presented to the user, and chooses standard star fields covering ranges of airmass, color, and time necessary to monitor atmospheric extinction and produce a photometric solution. The software determines when additional standard star fields are unnecessary, and selects survey calibration fields according to availability and priority. Other automated features of MOP, such as maintaining the focus and keeping a night log, are also built around still functional manual interfaces, allowing the observer to be as active in observing as desired; MOP's automated features may be used as tools for manual observing, ignored entirely, or allowed to run the telescope with minimal supervision when taking routine data.

In this paper we present the design of the control software for the LBT NIR spectroscopic Utility with Camera and Integral- Field Unit for Extragalactic Research (LUCIFER) which is one of the first-light instruments for the Large Bin-ocular Telescope (LBT) on Mt. Graham, Arizona. The LBT will be equipped with two identical LUCIFER instruments for both mirrors. Furthermore we give an overview of the intended hardware structure of the instrument. Since the project requires a detailed and exact modeling of the software we present UML diagrams starting with an overall model down to use case, activity and class diagrams including an example for one special instrument unit

We report on the status of the Cassegrain Instrument Automatic Exchanger (CIAX) control system for the Subaru Telescope. Devices controlled by a shell program in the previous version are now controlled by a macro. It can now be operated safely from remote site. Features of the new system are: 1. New macro. The new macro has two features: (1) Action skip. The macro can skip actions that have been executed earlier. It judges whether to skip by checking the status of devices. Resumption of interrupted macro or reversal from halfway of a process is possible. (2) Macro flexibility: The script has every possible sequential action and chooses actions by checking device status. For instance, it can determine whether the cart is at the telescope or at one of the instrument standby flanges and select a proper hookup command. 2. GUI for macro operation and CGI for rewriting setup files. The new GUI uses a commercial instrument control language. A CGI application accesses setup files. 3. Omni-directional Infrared (IR) LAN. Omni-directional IR LAN is being tested for the cart because radio frequency wireless LAN is prohibited on Mauna Kea to avoid interference to radio telescopes. Conventional IR LAN failed because of its directionality. The CIAX system is now routinely used for instrument exchange. For complete automatic operation, there are still a few tasks left, such as macro-controlled instrument shutdown and restarting, standardizing interfaces and procedure for all instruments and further increasing reliability which is higher already compared to conventional manual exchange.

The Instrument Group in the National Research Council of Canada's Herzberg Institute of Astrophysics develops instrumentation for large Astronomical telescopes including Altair (Gemini's ALTitude conjugate Adaptive optics for the InfraRed). This paper discusses how we responded to a need for adaptive intelligence and complex choreography and sequencing of mechanisms in the design of Altair's motion control systems. Our primary goal has been to maximize code reusability without sacrificing performance or flexibility.

Mira is the name of a program that measures and improves the image quality of the Keck Telescopes by correcting misalignments of the secondary mirror and adjusting the segments of the primary mirror. It is used regularly to achieve optimal focus calibration. Mira is completely written in Java. During the design phase, several software design patterns were followed resulting in short implementation times and a robust product. In this paper, we first discuss the operation of Mira, and then we present four examples of design patterns, describing the problem, the solution and the implementation.

We developed the telescope control software for the 188cm telescope of Okayama Astrophysical Observatory (OAO) based on Java technology. Basically, the software consists of two processes running on separate Java virtual machines; one of which is the “Command Dispatcher (CD)” and the other is the “User Interface (UI)”. Among the two, CD is the main engine/server of the telescope control, whereas UI is just a client. The “standard” UI we provide is a graphical user interface written in Java/Swing. CD communicates with the local control units (LCUs) of the telescope through RS232C. CD is a Java multi-thread program, in which a number of threads run simultaneously. The threads running in CD are the follows: UNIX socket servers for external communications, socket opener for on-demand open/close of a socket port, socket client manager, auto-guider and dome watcher, internal command dispatcher, status manager, status collector, RS232C writer and reader, logger, and control units. The above “control units” are software models (“objects”) of the telescope system. We introduced four control units- “Telescope”, “Dome”, “Weather-Monitor”, and “Pointing”- for telescope control. The first three units are simple software models of the real-worlds devices. The last one, “Pointing”, is a unit which abstracts pointing procedure of the telescope. CD and UI communicate with each other using UNIX socket. The command protocol of this communication is fairly simple, and observation instruments, auto guider, or additional UI for remote observation are also able to communicate with CD through socket using this protocol. CD opens and closes socket ports for communication on demand according to the request of client process (UI, instruments etc.), so that any clients can be connected to CD dynamically.

This paper describes the configuration of the observational stations belonging to the RETRO (REd de Telescopios ROboticos) network of robotic telescopes, operated by Centro de Astrobiologia. This network is composed, at the moment, by two 50 cm plus one 40 cm robotic telescopes installed in remote observatories (several hundred km away from each other), that operate autonomously without real-­time human supervision. This project is devoted to the applications of astrometric and photometric astronomical observations with robotic telescopes for systematic research in fields relevant to astrobiology: photometric detection of extrasolar planets, photometric follow­-up of solar­-type stars, and astrometry of near­-Earth objects (NEOs). To this purpose, the telescopes are equipped with CCD cameras for direct imaging, and photometric wide and medium-­band filters.

In the traditional, manned observatory, an astronomer must continually be weighing together many factors during the course of an observing run in order to make an appropriate decision on the course of action at that time. Weather conditions may force suspension of the observing program to protect the telescope, later to be resumed when conditions improve. Power outages may force controlled shutdown of computers and other hardware. Changes in sky condition may require on-the-fly changes to the scheduled program. For the Liverpool Telescope (LT), the Robotic Control System (RCS) is designed to act as a replacement for the duty astronomer. The system is required to be robust, reliable and adaptable e.g. to future instrument configurations and varying operational objectives. Consequently, object-oriented techniques which promote modularity and code re-use have been employed throughout the design of this system to facilitate maintainance and future upgrading. This paper describes the task management architecture (TMA) - a configurable, pattern based object model defining the cognitive functionality of the RCS, the environment monitoring architecture (EMA) - a configurable, rule-based decision making paradigm and the use of our proprietary Java message system (JMS) communications architecture to control the telescope and associated instrumentation.

32-bit database application with multidocument interface for Windows has been developed to calculate absolute energy distributions of observed spectra. The original database contains wavelength calibrated observed spectra which had been already passed through apparatus reductions such as flatfielding, background and apparatus noise subtracting. Absolute energy distributions of observed spectra are defined in unique scale by means of registering them simultaneously with artificial intensity standard. Observations of sequence of spectrophotometric standards are used to define absolute energy of the artificial standard. Observations of spectrophotometric standards are used to define optical extinction in selected moments. FFT algorithm implemented in the application allows performing convolution (deconvolution) spectra with user-defined PSF. The object-oriented interface has been created using facilities of C++ libraries. Client/server model with Windows Socket functionality based on TCP/IP protocol is used to develop the application. It supports Dynamic Data Exchange conversation in server mode and uses Microsoft Exchange communication facilities.

The Deep Imaging Multi-Object Spectrograph (DEIMOS)was delivered to the Keck II telescope during February 2002, and has been commissioned in the several months since then. Most of the instrument is in a barrel that rests on a cradle at the Nasmyth focus, and rotates to track field rotation. This paper describes the architecture of the rotator control software, including the communications protocols, time synchronization with the telescope control software, methods adopted for meeting the real-time control requirements, safety issues for a multi-ton rotating mass, and unusual position encoder challenges.

EMIR (Espectrógrafo Multiobjeto Infrarrojo) is a wide-field, near-infrared, multi-object spectrograph, with image capabilities, which will be located at the Nasmyth focus of GTC (Gran Telescopio Canarias). It will allow observers to obtain many intermediate resolution spectra simultaneously, in the nIR bands Z, J, H, K. A multi-slit mask unit will be used for target acquisition. This paper shows an overview of the EMIR software. Its architecture is distributed with real time features, having in mind to build a reusable, maintainable and inexpensive system. In this paper, we outline the main performances of the current design and some examples already implemented are given.

We describe our progress in the development of a software package to control a Fabry-Pérot interferometer (FPI) at the Big Bear Solar Observatory (BBSO). The FPI is a key part of our new Visible-Light Imaging Magnetograph (VIM). We describe the software libraries and methods that we use to develop the software. We also present specifications and characteristics of this new instrument.

Ground based testing is a critical and costly part of component, assembly, and system verifications of large space telescopes. At such tests, however, with integral teamwork by planners, analysts, and test personnel, segments can be included to validate specific analytical parameters and algorithms at relatively low additional cost. This paper presents analytical verification and validation segments currently added to ambient and vacuum cryogenic testing of Advanced Mirror System Demonstrator (AMSD) assemblies for the Next Generation Space Telescope (NGST) project. The test segments for workmanship testing, cold survivability, and cold operation optical throughput are supplemented by segments for analytical verifications of structural, thermal, and optical parameters. Utilizing integrated modeling and separate materials testing, the paper continues with analyses to be performed for AMSD testing, currently slated for calendar year 2003. These segments form a well-verified portion of the integrated modeling being conducted on AMSD for NGST performance predictions.

When software is written the developer will typically test error conditions as time progresses. Rarely will the developer have the time to go back and re-test all error conditions after every code change. This software provides a means to create a suite of software tests that can be run automatically as the code is developed. The developer can add additional tests as development proceeds and avoid the extra time at the end of a project to re-run tests manually. This system has been used to test both hardware and software reliability. The tool is flexible, informative, and invaluable when it comes to ensuring quality software. It has been used for acceptance tests for Gemini's Data Handling System, Multi-Object Spectrograph, Adaptive Optics System, and CFHT's Mega Prime instrument.

To meet the needs of the SOAR 4.2-m telescope first-generation instrument suite, as well as new instruments for the Blanco 4-m telescope, we developed a new camera controller system called ArcVIEW. In order to provide a strong foundation and rapid development cycle, we decided to build the system using National Instrument's LabVIEW environment. The advantages of this approach centers on the tools available for rapid prototyping, integration and testing of components. Over the past 2 years, we have taken ArcVIEW from a design document to the point of controlling two new instruments being built at CTIO. The IR imager, ISPI, will complete final testing this semester and go into use on the Blanco telescope in September 2002. The second instrument, the SOAR Optical Imager, is due for completion this semester and will be the commissioning instrument for the SOAR telescope, for which first light is expected in early 2003.

The Telescope Performance Monitor (TPM) installed at the Sloan Digital Sky Survey (SDSS) located at Apache Point Observatory provides access to real-time and archived engineering data. The modularity present in the underlying Experimental Physics and Industrial Control System (EPICS) toolkit allows the observers and operations staff to develop their own approaches to data access and analysis. These techniques are summarized and the use of the TPM to solve critical project issues including analysis and correction of thermal management problems are presented.

OSIRIS is an infrared integral-field spectrograph being built for the Keck AO system. OSIRIS presents novel data reduction and user-interaction challenges which are addressed by software being developed for OSIRIS. The complex raw data frames, containing up to 4096 interleaved spectra, are reduced in real-time and meaningfully displayed for quality-of-observation feedback to observers. Following an observing night, data are optimally reduced to science-quality data cubes in a semi-automated fashion. Further, the software must efficiently coordinate OSIRIS' spectroscopic observations with the SHARC off-axis imager and the AO system. To meet these demands, OSIRIS software is comprehensive and integrates the planning, execution, and reduction of observations. Facilitating this architecture is the formulation of observations into 'datasets', rather than into individual frames. Datasets are functional groups of frames organized by the needs and capabilities of the data reduction software (DRS). A typical dataset consists of dithered OSIRIS observations, coupled with associated off-axis AO PSF imagery from SHARC. A Java-based planning tool enables 'sequences' of datasets to be planned and saved both prior to and during observing sessions. An execution client interprets these XML-based files, and configures the hardware servers for OSIRIS, SHARC, and AO before executing the observations. As observations are completed, extensive information about the instrument and observatory are collated in an archival relational database. The DRS then uses information in the database, as well as archived calibration data and SHARC PSF data to produce a final science-quality data product, which may include differential refraction corrections, 3D PSF modeling/deconvolution, and OH-suppression.

The CHARA Array at Mt. Wilson consists of six telescopes spread over hundreds of meters of rugged territory. Making efficient use of such a large physical instrument requires automation and tele-operation of the distributed resources. One system which is key to making daily operations routine is the enclosure control system, which is used to open and close the walls of the enclosure in order to enable quick equilibration of the telescope with its environment in order to minimize ground seeing effects on observations. This paper describes this enclosure control system, which is a distributed hardware/software system consisting of software running on a central control station in the operations room, together with software and hardware installed on six remote computers. The system must be robust in the presence of absent or intermittent nodes or network connections, must provide for both manual or remote control of the enclosures, and must provide for hardware and personnel safety. Remote operation of the system from Atlanta, Georgia has been demonstrated, and the system has proven extremely robust in regular use to date.

We describe the recent upgrade of the Manchester Echelle Spectrometer, currently in use at San Pedro Mártir. This upgrade has included a user interface and a new CCD acquisition software. The spectrometer control is now done by a microcontroller, whose inputs are new sensors and encoders installed inside the spectrometer. The instrument control is now fully carried out from a graphical user interface running in a personal computer. The acquisition computer sends the images to the GUI through an ethernet link. In this paper, we present the general scheme and the programs developed for Linux (in C++ and Tcl/Tk) that permits an easy integral operation of the instrument, as well as the creation of scripts intended to the optimization of the observing run and the future interaction with the telescope and the guider. This upgraded system has been operated successfully during several campaigns in the 2.1-meter telescope at Observatorio Astronómico Nacional in San Pedro Mártir.

This paper describes the new Swedish solar telescope control system which is currently in the final phases of testing and tuning. The telescope has two current controlled motors per axis and encoder resolution of 0.0016 arcsecond per pulse. The servo consists of a cascaded position-velocity loop system implemented on a Compaq Alpha workstation class computer. The servo position correction loop runs at a frequency of 100 Hz whilst the faster velocity loop runs at 1KHz. This choice of servo allows a methodical tuning of gains because each gain is correcting a seperate frequency range. We shall describe the mechanical design employed in the telescope and the computer control. The real time requirements of the control servo will be explained along with how we have used standard commercial hardware and operating system to achieve this.

OSIRIS (Optical System for Imaging and low/intermediate-Resolution Integrated Spectroscopy) is an instrument designed to obtain images and low resolution spectra of astronomical objects in the optical domain (from 365 through 1000nm). It will be installed on Day One (middle of 2004) in the Nasmyth focus of the 10-meter Spanish GTC Telescope. This paper shows an overview of the OSIRIS instrument software. Its architecture is distributed with real time features, having in mind to build a reusable, maintainable and inexpensive system. In this paper, we outline the main performances of the current design and some examples already implemented are given.

The VLT Survey Telescope (VST) is a cooperative program between the European Southern Observatory (ESO) and the INAF Capodimonte Astronomical Observatory (OAC), Naples, for the study, design, and realization of a 2.6-m wide-field optical imaging telescope to be operated at the Paranal Observatory, Chile. The telescope design, manufacturing and integration are provided and under responsibility of the Technology Working Group (TWG) of OAC. The VST has been specifically designed to carry out stand-alone observations in the UV to I spectral range and to supply target databases for the ESO Very Large Telescope (VLT). The VST control software will operate the telescope, all the auxiliary subsystems and will manage the interfaces toward the instrumentation. The paper will describe the architecture of the software system, including the solutions adopted to be compliant with the ESO standard software environment.

Complex telescope systems such as interferometers tend to rely heavily on hard real-time operating systems (RTOS). It has been standard practice at NASA's Jet Propulsion Laboratory (JPL) and many other institutions to use costly commercial RTOSs and hardware. After developing a real-time toolkit for VxWorks on the PowerPC platform (dubbed RTC), the interferometry group at JPL is porting this code to the real-time Application Interface (RTAI), an open source RTOS that is essentially an extension to the Linux kernel. This port has the potential to reduce software and hardware costs for future projects, while increasing the level of performance. The goals of this paper are to briefly describe the RTC toolkit, highlight the successes and pitfalls of porting the toolkit from VxWorks to Linux-RTAI, and to discuss future enhancements that will be implemented as a direct result of this port. The first port of any body of code is always the most difficult since it uncovers the OS-specific calls and forces “red flags” into those portions of the code. For this reason, It has also been a huge benefit that the project chose a generic, platform independent OS extension, ACE, and its CORBA counterpart, TAO. This port of RTC will pave the way for conversions to other environments, the most interesting of which is a non-real-time simulation environment, currently being considered by the Space Interferometry Mission (SIM) and the Terrestrial Planet Finder (TPF) Projects.