Proc. SPIE. 10707, Software and Cyberinfrastructure for Astronomy V
KEYWORDS: Observatories, Telescopes, Control systems, Space telescopes, Software development, Astronomical telescopes, Software engineering, Systems engineering, Computer architecture, Process engineering
The SKA (Square Kilometre Array) Telescope Manager (TM) is the core package of the SKA Telescope: it is aimed at scheduling observations, controlling their execution, monitoring the telescope health status, diagnosing and fixing its faults and so on. Following the adoption of the Views and Beyond (V and B) approach  of the Software Engineering Institute (SEI ), it was discussed and agreed upon to take the opportunity to setup a TM Architecture Team (TMAT) composed by a combination of team members (who drove much of the work towards the main deliverables for the final review) and others (who can help shape the architectural design). The TMAT has to make sure that the main deliverables are well aligned with the overall TM architecture (including ensuring that the SEI approach is followed to the level agreed upon), and that there are no gaps and that cross-cutting issues are taken care of properly. This paper wants to analyze the challenges that the team has to face together with the solutions proposed to ensure that the quality of the deliverables are reached.
The international Square Kilometre Array (SKA) project to build two radio interferometers is approaching the end of its design phase, and gearing up for the beginning of formal construction. A key part of this distributed Observatory is the overall software control system: the Telescope Manager (TM). The two telescopes, a Low frequency dipole array to be located in Western Australia (SKA-Low) and a Mid-frequency dish array to be located in South Africa (SKA-Mid) will be operated as a single Observatory, with its global headquarters (GHQ) based in the United Kingdom at Jodrell Bank. When complete it will be the most powerful radio observatory in the world. The TM software must combine the observatory operations based at the GHQ with the monitor and control operations of each telescope, covering the range of domains from proposal submission to the coordination and monitoring of the subsystems that make up each telescope. It must also monitor itself and provide a reliable operating platform. This paper will provide an update on the design status of TM, covering the make-up of the consortium delivering the design, a brief description of the key challenges and the top level architecture, and its software development plans for tackling the construction phase of the project. It will also briefly describe the consortium’s response to the SKA Project’s decision in the second half of 2016 to adopt the processes set out by the Software Engineering Institute (SEI) for system architecture design and documentation, including a re-evaluation of its deliverables, documentation and approach to internal reviews.
Many large projects including major astronomy projects are adopting a Model Based Systems Engineering approach. How far is it possible to get value for the effort involved in developing a model that accurately represents a significant project such as SKA? Is it possible for such a large project to ensure that high-level requirements are traceable through the various system-engineering artifacts? Is it possible to utilize the tools available to produce meaningful measures for the impact of change?
This paper shares one aspect of the experience gained on the SKA project. It explores some of the recommended and pragmatic approaches developed, to get the maximum value from the modeling activity while designing the Telescope Manager for the SKA. While it is too early to provide specific measures of success, certain areas are proving to be the most helpful and offering significant potential over the lifetime of the project.
The experience described here has been on the 'Cameo Systems Modeler' tool-set, supporting a SysML based System Engineering approach; however the concepts and ideas covered would potentially be of value to any large project considering a Model based approach to their Systems Engineering.
The Square Kilometre Array (SKA) will be the world's most advanced radio telescope, designed to explore some of the biggest questions in astronomy today, such as the epoch of re-ionization, the nature of gravity and the origins of cosmic magnetism. SKA1, the first phase of SKA construction, is currently being designed by a large team of experts world-wide. SKA1 comprises two telescopes: a 200-element dish interferometer in South Africa and a 130000-element dipole antenna aperture array in Australia. To enable the ground-breaking science of the SKA an advanced Observation Management system is required to support both the needs of the astronomical community users and the SKA Observatory staff. This system will ensure that the SKA realises its scientiffc aims and achieves optimal scientific throughput. This paper provides an overview of the design of the system that will accept proposals from SKA users, and result in the execution of the scripts that will obtain science data, taking in the stages of detailed preparation, planning and scheduling of the observations and onwards tracking. It describes the unique challenges of the differing requirements of two telescopes, one of which is very much a software telescope, including the need to schedule the data processing as well as the acquisition, and to react to both internally and externally discovered transient events. The scheduling of multiple parallel sub-array use is covered, along with the need to handle commensal observing - using the same data stream to satisfy the science goals of more than one project simultaneously. An international team from academia and industry, drawing on expertise and experience from previous telescope projects, the virtual observatory and comparable problems in industry, has been assembled to design the solution to this challenging but exciting problem.
The Square Kilometre Array (SKA) will be the world's most advanced radio telescope, designed to be many times times more sensitive and hundreds of times faster at mapping the sky than today's best radio astronomy facilities. The scale and advanced capabilities of the SKA present technical challenges for co-ordinating and executing observations. This paper discusses the requirements placed on the SKA's observation sequencer - the Observation Execution Tool - and the functions it must perform. A design and prototype implementation of the Observation Execution Tool are presented, with initial results showing that a Python implementation using a message-driven component architecture could be capable of meeting the SKA's requirements.
The SKA radio telescope project is building two telescopes, SKA-Low in Australia and SKA-Mid in South Africa respectively. The Telescope Manager is responsible for the observations lifecycle and for monitoring and control of each instrument, and is being developed by an international consortium. The project is currently in the design phase, with the Preliminary Design Review having been successfully completed, along with re-baselining to match project scope to available budget. This report presents the status of the Telescope Manager work, key architectural challenges and our approach to addressing them.
There are several large ground-based telescopes currently under development such as the SKA and CCAT in radio as
well as several 30m-class in the optical. A common challenge that all of these telescopes are facing is estimating the cost
of design, construction and maintenance of their required software. This paper will present a cost breakdown of the
monitoring and control software packages implemented for ASKAP including the effort spent to develop and maintain
the in-house code and the effort saved by using third-party software, such as EPICS. The costing for ASKAP will be
compared to those for the monitoring and control software of other large ground-based telescopes such as ALMA and
VLT. This comparison will highlight trends and commonalities in the costing and provides a useful guide for costing
future telescope control software builds or upgrades and the ongoing maintenance cost.
The ALMA Observatory is currently operating ′Early Science′ observing. The Cycle0 and Cycle1 Calls for Proposals are
part of this Early Science, and in both the ALMA Observing Tool plays a crucial role. This paper describes how the
ALMA OT tackles the problem of making millimeter/sub-millimeter interferometry accessible to the wider community,
while allowing "experts" the power and flexibility they need.
We will also describe our approach to the challenges of supporting multiple customers, and explore the lessons learnt
from the Early Science experiences. Finally we look ahead to the challenges presented by future observing cycles.
The Cornell Caltech Atacama Telescope1 is a 25m aperture sub-millimeter wavelength telescope to be built in northern
Chile at an altitude of 5600m. Like any modern telescope, CCAT will require a powerful and comprehensive control
system; writing one from scratch is not affordable, so the CCAT TCS must be based, at least in part, on existing
software. This paper describes how the search for a suitable system (or systems) was carried out, looks at the criteria
used to judge the feasibility of various approaches to developing the new system, and suggests the further studies needed
to validate the choices. Although the purpose of the study was to find a control system for a specific telescope with its
own particular technical requirements, many of the factors considered, such as maintainability, the ability to adapt to new
requirements in the future and so on, are of concern to all telescopes. Consequently, the processes used to select the
system for CCAT are relevant to other projects faced with the same decision, even if the conclusions turn out to be
The new observatories currently being built, upgraded or designed represent a big step up in terms of complexity (laser
guide star, adaptive optics, 30/40m class telescopes) with respect to the previous generation of ground-based telescopes.
Moreover, the high cost of observing time imposes challenging requirements on system reliability and observing
efficiency as well as challenging constraints in implementing major upgrades to operational observatories. Many of the
basic issues are common to most of the new projects, while each project also brings an additional set of very specific
challenges, imposed by the unique characteristics and scientific objectives of each telescope. Finding ways to share the
solution and the risk for these common problems would allow the teams in the different projects to concentrate more
resources on the specific challenges, while at the same time realizing more reliable and cost efficient systems. In this
paper we analyze the many dimensions that might be involved in sharing and re-using observatory software (e.g.
components, design, infrastructure frameworks, applications, toolkits, etc.). We also examine observatory experiences
and technology trends. This work is the continuation of an effort started in the middle of 2007 to analyze the trends in
software for the control systems of large astronomy projects.
The "Project Data Model" (PDM) is a model of the information that describes an astronomical observing project. In this
paper we consider the PDM to cover the Proposal and Observing Preparation phases (also often called Phase 1 and Phase
2), and also the intermediate phase of reviewing and approving the project. At the back end of observing, the production
of calibrated or partially calibrated science data, such models or data structures have been common for some time, albeit
evolving (FITS, Measurement Set, etc.), but modelling the front end of observing is a relatively recent phenomenon, with
most observatories creating their own versions of the "PDM". This paper describes work towards a common PDM for
two radio observatories that are in development, ALMA and the EVLA. It goes further to explore the prospect of a wider
common PDM that could be shared across astronomy. Is there a case to produce such a common PDM? And is it
feasible? It is likely that a common model for Phase 1, an observing proposal, is possible. However, for a number of
reasons a common model for Phase 2 is a much tougher challenge.
We present a report on the current development status of the ALMA Observing Tool, describing how the tool operates as
an integrated environment for proposal and program preparation. The paper also covers the science-oriented graphical
tools for both spatial and spectral setup, their system-oriented equivalents, local oscillator and correlator setup assistants
as well as program validation.
A number of tools exist to aid in the preparation of proposals and observations for large ground and space-based observatories (VLT, Gemini, HST being examples). These tools have transformed the way in which astronomers use large telescopes. The ALMA telescope has a strong need for such a tool, but its scientific and technical requirements, and the nature of the telescope, provide some novel challenges. In addition to the common Phase I (Proposal) and Phase II (Observing) preparation the tool must support the needs of the novice alongside the needs of those who are expert in millimetre/sub-millimetre aperture synthesis astronomy. We must also provide support for the reviewing process, and must interface with and use the technical architecture underpinning the design of the ALMA Software System. In this paper we describe our approach to meeting these challenges.
An update on the design status of the UKIRT Wide Field Camera (WFCAM) is presented. WFCAM is a wide field infrared camera for the UK Infrared Telescope, designed to produce large scale infrared surveys. The complete system consists of a new IR camera with integral autoguider and a new tip/tilt secondary mirror unit. WFCAM is being designed and built by a team at the UK Astronomy Technology Centre in Edinburgh, supported by the Joint Astronomy Centre in Hawaii. The camera uses a novel quasi-Schmidt camera type design, with the camera mounted above the UKIRT primary mirror. The optical system operates over 0.7 - 2.4 μm and has a large corrected field of view of 0.9° diameter. The focal plane is sparsely populated with 4 2K x 2K Rockwell HAWAII-2 MCT array detectors, giving a pixel scale of 0.4 arcsec/pixel. A separate autoguider CCD is integrated into the focal plane unit. Parallel detector controllers are used, one for each of the four IR arrays and a fifth for the autoguider CCD.
In 1996, it was proposed to build a near-infrared imager for the 3.8-m UK Infrared Telescope in Hawaii, to exploit the 1024 pixel format detectors that were then becoming available. In order to achieve a fast delivery, the instrument was kept simple and existing designs were reused or modified where possible. UFTI was delivered within 2.5 years of the project start. The instrument is based around a 1k Rockwell Hawaii detector and a LSR Astrocam controller and uses the new Mauna Kea optimized J,H,K filter set along with I and Z broad-band filters and several narrow-band line filters. The instrument is cooled by a CTI cry-cooler, while the mechanisms are operated by cold, internal, Bergelahr stepping motors. On UKIRT it can be coupled to a Fabry-Perot etalon for tunable narrow-band imaging at K, or a waveplate for imaging polarimetry through 1-2.5 μm; the cold analyzer is a Barium Borate Wollaston prism. UFTI was designed to take full advantage of the good image quality delivered by UKIRT on conclusion of the upgrades program, and has a fine scale of 0.09 arcsec/pixel. It is used within the UKIRT observatory environment and was the first instrument integrated into ORAC, the Observatory Reduction and Acquisition Control System. Results obtained during instrument characterization in the lab and over the last 3 years on UKIRT are presented, along with performance figures. UFTI has now been used on UKIRT for several hundred nights, and aspects of instrument performance are discussed.
This paper describes an ambitious new wide field IR camera for the 3.8m UK IR Telescope (UKIRT), located on Mauna Kea, Hawaii. The camera, currently under design at the UK Astronomy Technology Center, will include 4 2048 by 2048 pixel focal plane array IR detectors operating over a wavelength range of 1-2.5 micrometers . The optics provide a 1 degree diameter corrected field of view and a pixel scale of 0.4 arcsec per pixel. A novel Schmnidt type optical design allows the large field to be imaged with excellent image quality. The optical design includes a cold stop to maximize rejection of background radiation and stray light. Precise microstepping will be used to improve sampling. Four parallel data acquisition and processing channels will be used to cope with the large data rates expected. It is envisaged that a substantial fraction of UKIRT time will be devoted to large area sky surveys once WFCAM is operational, resulting in a unique IR catalogue containing hundreds of millions of objects.
The steady improvement in telescope performance at UKIRT and the increase in data acquisition rates led to a strong desired for an integrated observing framework that would meet the needs of future instrumentation, as well as providing some support for existing instrumentation. Thus the Observatory Reduction and Acquisition Control (ORAC) project was created in 1997 with the goals of improving the scientific productivity in the telescope, reducing the overall ongoing support requirements, and eventually supporting the use of more flexibly scheduled observing. The project was also expected to achieve this within a tight resource allocation. In October 1999 the ORAC system was commissioned at the United Kingdom Infrared Telescope.
An imaging spectrometer is being designed to take advantage of recent improvements in the image quality achieved at the UK Infrared Telescope. The realization of near-diffraction limited imaging at two microns brings with it the possibility of significant improvements in sensitivity to IR observations. UIST will provide a versatile facility for high spatial resolution imaging and spectroscopy in the 1-5 micrometers wavelength range. We will present the opto-mechanical design of this new instrument, highlighting the innovative features. These include provision of multiple pixel scales within the camera and polarimetry via a Wollaston prism. One of the most challenging areas of the design is the inclusion of a cryogenic integral field unit for area spectroscopy over a 5 inch field. The spectroscopic modes include cross- dispersed spectroscopy over the complete 1-2.5 micrometers wavelength ranges and moderate resolution long slit or area spectroscopy over the complete 1-5 micrometers range. A higher resolution mode will also the included. This will allow USTI to take advantage of the very low backgrounds to be found between OH sky lines. The instruments will incorporate a 1024 X 1024 Indium Antimonide array from SBRC. The development of the IR array controller for UIST will also be discussed.
For the past seven years observing with the major instruments at the United Kingdom IR Telescope (UKIRT) has been semi-automated, using ASCII files top configure the instruments and then sequence a series of exposures and telescope movements to acquire the data. For one instrument automatic data reduction completes the cycle. The emergence of recent software technologies has suggested an evolution of this successful system to provide a friendlier and more powerful interface to observing at UKIRT. The Observatory Reduction and Acquisition Control (ORAC) project is now underway to construct this system. A key aim of ORAC is to allow a more complete description of the observing program, including the target sources and the recipe that will be used to provide on-line data reduction. Remote observation preparation and submission will also be supported. In parallel the observatory control system will be upgraded to use these descriptions for more automatic observing, while retaining the 'classical' interactive observing mode. The final component of the project is an improved automatic data reduction system, allowing on-line reduction of data at the telescope while retaining the flexibility to cope with changing observing techniques and instruments. The user will also automatically be provided with the scripts used for the real-time reduction to help provide post-observing data reduction support. The overall project goal is to improve the scientific productivity of the telescope, but it should also reduce the overall ongoing support requirements, and has the eventual goal of supporting the use of queue- scheduled observing.
The Michelle Edict array control system is being built for use with the Michelle mid-infrared spectrometer/imager on UKIRT and Gemini. It will drive large format arrays, such as the Boeing/Rockwell 256 by 256 BIB and Raytheon/SBRC 320 by 240 IBC hybrid SiAs devices. It provides for rapid real-time processing and export to a host computer, storage and quick- look display of the data. To limit critical heat dissipation and mass, the system uses a minimum of front-end electronics at the telescope linked via digital fiber optics to custom- built PCI mezzanine cards. These are installed on several Heurikon Baja 4700 VME cards in an off telescope enclosure. This distributed architecture has small electrical infrastructure requirements and allows Michelle to be moved quickly between operation on UKIRT and Gemini with little impact on other instruments. The use of VxWorks on the Baja processors and the PCI standard allows the system to be easily ported to other VME processor boards supporting the PCI interface. Alongside a cryostat control system, edict interfaces to the data handling systems and the EPICS-based Gemini telescope control. On UKIRT, it will function under a UNIX-based observation control system that is being built to replace the existing VAX/VMS-based ADAM system.
First light with the advanced cooled grating spectrometer (CGS4) was achieved at the United Kingdom Infrared Telescope on February 4, 1991 following successful delivery of the instrument from the Royal Observatory, Edinburgh. We discuss the performance of CGS4 and summarize our experience in maintaining optimum array sensitivity. CGS4 is unique in that both the data acquisition and reduction can be almost completely automated, and the key elements of the software and their impact on observing are described. We discuss how various aspects of CGS4 such as the reproducibility of flat fields relate to the ability to provide users with flat-fielded, sky-subtracted spectra almost in real-time. We also discuss the problems of the variability of OH line emission and atmospheric transmission and describe the sky subtraction techniques which we have been using both at the telescope and in post observing analysis.