It is a top level science requirement that data from the Daniel K Inouye Solar Telescope (DKIST) is archived and made available to the world wide astronomical community. Data from DKIST must contain sufficient meta-data to allow proper post processing. This paper describes how the Telescope Control System (TCS), Wavefront Correction Control System (WCCS) and individual instrument control systems work together with the camera systems to provide the world coordinate information (WCI) meta-data for 2-d imaging detectors.
The Common Services Framework (CSF) is a software architecture developed at the National Solar Observatory for
control of the Advanced Technology Solar Telescope (ATST). The framework was designed with the intent to make it
independent of the ATST application and freely available to other projects. As part of the System Design phase for the
Telescope Control System upgrade and Next Generation Adaptive Optics projects at the W. M. Keck Observatory a
number of software frameworks and middleware were evaluated. Of those evaluated, CSF was selected as one of the
primary choices for all or part of the software architecture and will be pursued further in the next design phases. This
paper discusses the evaluation of CSF at Keck and some possible evolutions of the framework.
The Advanced Technology Solar Telescope (ATST) Common Services Framework (CSF) provides the
technical framework necessary to quickly and easily develop applications implementing the command-action-response
model. The ATST Base builds on top of CSF and provides applications that, with a few modifications, can be dropped
into a telescope control system or an instrument control system. This is done by extending the CSF Controller and
writing applications that perform some of the common tasks needed by telescope and instrument control systems. This
paper includes a general look at the Hardware Controller and an in-depth look at the Management Controller and Motion
Telescope and instrument control systems typically have multiple axes of motion that need to be coordinated.
Management Controllers allow a simple command to be given to a single Controller and then aggregated to multiple
worker Controllers who can perform multiple actions. Management Controllers aggregate the state and status of their
workers. The workers may be of the same type (e.g., multiple servo control systems) or of different types (e.g., two
different servo controllers, a hexapod controller, digital I/O controller and a camera controller).
Most users of turnkey motion control solutions use only a few of the commands that the motion control system
provides. The ATST Base Motion Controller abstracts the hardware, and provides a simple interface (focusing on a few
common instructions) to use in controlling different types of motion stages.
At future telescopes, adaptive optics systems will play a role beyond the correction of Earth's atmosphere.
These systems are capable of delivering information that is useful for instrumentation, e.g. if reconstruction
algorithms are employed to increase the spatial resolution of the scientific data. For the 4m aperture Advanced
Technology Solar Telescope (ATST), a new generation of state-of-the-art instrumentation is developed that will
deliver observations of the solar surface at unsurpassed high spatial resolution. The planned Visual Broadband
Imager (VBI) is one of those instruments. It will be able to record images at an extremely high rate and compute
reconstructed images close to the telescope's theoretical diffraction limit using a speckle interferometry algorithm
in near real-time. This algorithm has been refined to take data delivered by the adaptive optics system into
account during reconstruction. The acquisition and reconstruction process requires the use of a high-speed data
handling infrastructure to retrieve the necessary data from both adaptive optics system and instrument cameras.
We present the current design of this infrastructure for the ATST together with a feasibility analysis of the
The Advanced Technology Solar Telescope (ATST) has implemented a novel method for gathering header information
on data products. At the time of data collection, the specific state of the telescope and instrumentation needs to be
collected and associated with the saved data. The ATST performs this task by issuing a header request event across the
ATST event system. All observatory software components that are registered for the event and are participating in the
current experiment or observation report status information to a central header repository. Various types of header
request events may be selected for start or stop of individual frames, groups of frames, or entire observations. The final
data products are created by combining the data files with all or some of stored header information in the database. The
resulting data file may be generated in any possible format, including FITS. Much of the implementation of this
approach is integrated into the ATST technical framework, simplifying the development process for component writers
and ensuring consistent responses to header request events.
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.
Proc. SPIE. 6274, Advanced Software and Control for Astronomy
KEYWORDS: Control systems, Telecommunications, Observatories, Solar telescopes, Standards development, Computer architecture, Software development, Data communications, Software frameworks, Systems modeling
ATST control systems communicate by passing sets of attribute-value pairs between system components. Each set, or configuration, defines a required state for a component to match. To coordinate the control systems using configurations, every component must implement a consistent behavior. The ATST Controller provides a base class for components to use that implements a uniform life cycle and functional behavior for matching configurations. The ATST Controller class is one of the key elements of the ATST Common Services software framework.
The Controller class accepts input configurations though a simple command interface. The class is readily extended to subclasses that may perform detailed operations based on the configuration. Alternatively, ATST Controllers may be used in hierarchical systems that delegate actions to groups of lower level controllers. The Controller provides a simple configuration life cycle to determine the state of a configuration in a component. The Controller also enforces a separation of a component's command request and the ensuing action by executing each configuration in its own thread. This implementation also allows a Controller to execute simultaneous configurations, where the synchronization and exclusion details are left to the implementing subclass.
The Advanced Technology Solar Telescope (ATST) is designed as the premier ground-based solar telescope. With an expected lifetime of more than 25 years, a great deal of thought has been put into designing a software control system with the flexibility to adapt to changes in software technology through the lifetime of ATST. The goal is to have a software architecture that can be readily adapted to advances in software technologies. A significant aspect of this architecture is its independence from third-party tools, particularly communications middleware. This independence is achieved through a carefully-layered design that facilitates the process of replacing one service implementation with another by separating the functional and technical infrastructures within a container/component model. The paper presents the details of how ATST implements this separation and allows the quick replacement of one service implementation with another implementation using a toolbox metaphor. The toolbox provides a consistent external interface to services and service-related data while providing an internal interface that supports dynamic replacement of one service plugin with another.
The Virtual Solar Observatory (VSO) is a bottom-up grassroots approach to the development of a distributed data system for use by the solar physics community. The beta testing version of the VSO was released in December 2003. Since then it has been tested by approximately 50 solar physicists. In this paper we will present the status of the project, a summary of the community's experience with the tool, and an overview of the lessons learned.
The Advanced Technology Solar Telescope (ATST) is intended to be the premier solar observatory for experimental solar physics. The ATST telescope control software is designed to operate similar to current nighttime telescopes, but will contain added functionality required for solar observations. These additions include the use of solar coordinate systems, non-sidereal track rates, solar rotation models, alternate guide signal sources, the control of thermal loads on the telescope, unusual observation and calibration motions, and serendipitous acquisition of transient objects.
These requirements have resulted in a design for the ATST telescope control system (TCS) that is flexible and well-adapted for solar physics experiments. This report discusses both the classical design of the ATST TCS and the modifications required to observe in a solar physics environment. The control and servo loops required to operate both the pointing and wavefront correction systems are explained.
The Advanced Technology Solar Telescope (ATST) is intended to be the premier facility for experimental solar physics. A premium has been placed on operating ATST as a laboratory-style observatory to maximize the flexibility available to solar physicists. In particular, the main observation platform is a rotating coude platform supporting eight optical benches on which instruments may be assembled from available components. The Virtual Instrument Model has been developed to formalize the operation of a facility where instruments may exist for a single experiment before components are reassembled into a new instrument. The model allows the laboratory-style operation to fit easily within a typical modern telescope control system. This paper presents one possible implementation of the Virtual Instrument Model that is based on the container/component model becoming increasing popular in software development.
The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope in the world, providing a unique scientific tool to study the Sun and possibly other astronomical objects, such as solar system planets. We briefly summarize the science drivers and observational requirements of ATST. The main focus of this paper is on the many technical challenges involved in designing a large aperture solar telescope. The ATST project has entered the design and development phase. Development of a 4-m solar telescope presents many technical challenges. Most existing high-resolution solar telescopes are designed as vacuum telescopes to avoid internal seeing caused by the solar heat load. The large aperture drives the ATST to an open-air design, similar to night-time telescope designs, and makes thermal control of optics and telescope structure a paramount consideration. A heat stop must reject most of the energy (13 kW) at prime focus without introducing internal seeing. To achieve diffraction-limited observations at visible and infrared wavelengths, ATST will have a high order (order 1000 DoF) adaptive optics system using solar granulation as the wavefront sensing target. Coronal observations require occulting in prime focus, a Lyot stop and contamination control of the primary. An initial set of instruments will be designed as integral part of the telescope. First telescope design and instrument concepts will be presented.
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.
The SOLIS (Synoptic Optical Long-term Investigations of the Sun) project is constructing new telescopes to replace the Vacuum Telescope at Kitt Peak. Among other goals, SOLIS is to continue observations that have been in progress over the last 25 years, using a new set of instruments. Solar observing differs from other astronomical observing in several key ways: exposures tend to be short and yet still produce large volumes of data--the expected data rate is a sustained 56 MBytes per second with peaks of 132 MB/s. The overwhelming majority of observations are synoptic although the ability to respond to unscheduled events (e.g. solar flares) is a cornerstone of the system. Precise time constraints are typical observation requirements.
The new 8-meter class telescopes represent large investments by the development communities. This means that these telescopes must be operated efficiently to provide the best possible return on these investments and a great deal of effort has been made to provide control software that supports effective use of the telescopes. However, efficient use must be more than just keeping the telescopes operating; it is important that observers be provided tools that enable them work effectively. The Gemini 8 m Telescopes have developed a strategy for helping astronomers plan observations through the design of science programs. While there are a number of unique aspects to this strategy, this paper focuses on the methods used as the foundation for connecting astronomers to the facilities of the observatories during the design of science programs. The methods under development take advantage of emerging Internet technologies to help reduce the maintenance issues normally associated with supporting remote sites, while freeing users from many of the performance problems associated with web-based solutions.
The design of the software for the Gemini 8 m telescopes is nearly complete. Great care has been taken to develop a system with the flexibility to support astronomy into the next century without disassociating itself from the current methods of observing. The goal has been to design a system that supports the complexities involved in high performance telescope operation while providing an interface that is easy to operate in all modes from classical observing to modern queue-scheduled approaches. The resulting design has been crafted to augment the skills of observers and system operators and has produced a development strategy intended to encourage the interaction of scientists and developers.
The processing of high-level system commands within an experimental physics and industrial control system (EPICS) database application shares many issues with the design of EPICS motor control records in that the traditional synchronous/asynchronous record processing model is not adhered to. This paper presents the design of the Gemini CAD (command action directive) and CAR (command action response) EPICS database records and illustrates their use in a telescope mount control context dealing with the handling of repeated offset and slew commands.
The use of `scenarios' that describe desired telescope operating behavior can serve as an effective tool for ensuring a telescope design provides the functionality that is desired by the user community. This report examines the role of scenarios and the descriptions of how the system responds to these scenarios (`walk throughs') in the Gemini 8 m Telescopes Control System.
During 1993 we have upgraded our adaptive optics analysis software package to execute under an interactive, graphical user interface. This software may be used to evaluate a wide range of adaptive optics concepts, including constellations of multiple guide stars, multiconjugate deformable mirror configurations, and integrated adaptive optics/image postprocessing techniques. Adaptive optics system performance is evaluated in terms of mean optical transfer functions, mean point spread functions, and related quantities. These estimates account for the integrated effects of error sources including servo lag, fitting error, sensor noise, and anisoplanatism. They are computed using minimal variance wavefront reconstruction algorithms which will optimize system performance for the given operating conditions.