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We† provide an overview of the Model Based Systems Engineering (MBSE) language, tool, and methodology being used in our development of the Operational Plan for Large Synoptic Survey Telescope (LSST) operations. LSST’s Systems Engineering (SE) team is using a model-based approach to operational plan development to: 1) capture the topdown stakeholders’ needs and functional allocations defining the scope, required tasks, and personnel needed for operations, and 2) capture the bottom-up operations and maintenance activities required to conduct the LSST survey across its distributed operations sites for the full ten year survey duration. To accomplish these complimentary goals and ensure that they result in self-consistent results, we have developed a holistic approach using the Sparx Enterprise Architect modeling tool and Systems Modeling Language (SysML). This approach utilizes SysML Use Cases, Actors, associated relationships, and Activity Diagrams to document and refine all of the major operations and maintenance activities that will be required to successfully operate the observatory and meet stakeholder expectations. We have developed several customized extensions of the SysML language including the creation of a custom stereotyped Use Case element with unique tagged values, as well as unique association connectors and Actor stereotypes. We demonstrate this customized MBSE methodology enables us to define: 1) the rolls each human Actor must take on to successfully carry out the activities associated with the Use Cases; 2) the skills each Actor must possess; 3) the functional allocation of all required stakeholder activities and Use Cases to organizational entities tasked with carrying them out; and 4) the organization structure required to successfully execute the operational survey. Our approach allows for continual refinement utilizing the systems engineering spiral method to expose finer levels of detail as necessary. For example, the bottom-up, Use Case-driven approach will be deployed in the future to develop the detailed work procedures required to successfully execute each operational activity.

We present an overview of the Integration and Verification Testing activities of the Large Synoptic Survey Telescope (LSST) Camera at the SLAC National Accelerator Lab (SLAC). The LSST Camera, the sole instrument for LSST and under construction now, is comprised of a 3.2 Giga-pixel imager and a three element corrector with a 3.5 degree diameter field of view. LSST Camera Integration and Test will be taking place over the next four years, with final delivery to the LSST observatory anticipated in early 2020. We outline the planning for Integration and Test, describe some of the key verification hardware systems being developed, and identify some of the more complicated assembly/integration activities. Specific details of integration and verification hardware systems will be discussed, highlighting some of the technical challenges anticipated.

The Radiometric All-Sky Infrared Camera (RASICAM) has been operating on Cerro Tololo for over two years looking for clouds in the 10 to 12 micron IR band. Every 90 seconds each night RASICAM collects an integrated image of sky conditions and reports them to the Blanco telescope control system (TCS) to be shared with other instruments. We report on the RASICAM design, calibration and performance of the system. Additionally, correlation with conditions as observed in the Dark Energy Camera (DECam) will be presented.

The Dark Energy Survey (DES) is a next generation optical survey aimed at understanding the accelerating expansion of the universe using four complementary methods: weak gravitational lensing, galaxy cluster counts, baryon acoustic oscillations, and Type Ia supernovae. To perform the 5000 sq-degree wide field and 30 sq-degree supernova surveys, the DES Collaboration built the Dark Energy Camera (DECam), a 3 square-degree, 570-Megapixel CCD camera that was installed at the prime focus of the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). DES started its first observing season on August 31, 2013 and observed for 105 nights through mid-February 2014. This paper describes DES “Year 1” (Y1), the strategy and goals for the first year's data, provides an outline of the operations procedures, lists the efficiency of survey operations and the causes of lost observing time, provides details about the quality of the first year's data, and hints at the “Year 2” plan and outlook.

The Dark Energy Camera (DECam) is a new 520 Mega Pixel CCD camera with a 3 square degree field of view built for the Dark Energy Survey (DES). DECam is mounted at the prime focus of the Blanco 4-m telescope at the Cerro-Tololo International Observatory (CTIO). DES is a 5-year, high precision, multi-bandpass, photometric survey of 5000 square degrees of the southern sky that started August 2013. In this paper we briefly review SISPI, the data acquisition and control system of the Dark Energy Camera and follow with a discussion of our experience with the system and the lessons learned after one year of survey operations.

Wavefront sensing and the Active Optics System (AOS) of the Dark Energy Camera (DECam) at the CTIO 4-meter Blanco telescope are described. DECam utilizes four pairs of intra/extra-focal CCDs located on the edge of the focal plane for wavefront sensing. Out-of-focus stars are selected, individually fit to a pupil plane Zernike expansion and then collectively analyzed in the time between exposures. The AOS uses this information to control the prime-focus camera’s five degrees of freedom. The AOS is now in routine use, operating with unsupervised control of the focus and camera alignment, both for the Dark Energy Survey and community observing. The design, commissioning and operation of the AOS along with results from the wavefront measurements are described. In particular, wavefront measurements of the complete optical system, including primary mirror aberrations, are shown. Lastly, preliminary results using these wavefront measurements to model the DECam point spread function are presented.

BigBOSS is a proposed ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of large scale structure. It consists of a fiber-fed multi-object spectrograph designed to be installed on the Mayall 4-meter telescope at Kitt Peak, Arizona. BigBOSS includes an optical corrector assembly and 5000-fiber-positioner focal plane assembly that replace the existing Mayall prime focus hardware. 40-meter long optical fiber bundles are routed from the focal plane, through the telescope declination and right ascension pivots, to spectrographs in the thermally insulated FTS Laboratory, immediately adjacent to the telescope. Each of the ten spectrographs includes three separate spectral bands. The FTS Laboratory also houses support electronics, cooling, and vacuum equipment. The prime focus assembly includes mounts for the existing Mayall f/8 secondary mirror to allow observations with Cassegrain instruments. We describe the major elements of the BigBOSS instrument, plans for integrating with the Telescope, and proposed modifications and additions to existing Mayall facilities.

The Dark Energy Camera (DECam) is a new 520 Mega Pixel CCD camera with a 3 square degree field of view designed for the Dark Energy Survey (DES). DES is a high precision, multi-bandpass, photometric survey of 5000 square degrees of the southern sky. DECam is currently being installed at the prime focus of the Blanco 4-m telescope at the Cerro- Tololo International Observatory (CTIO). In this paper we describe SISPI, the data acquisition and control system of the Dark Energy Camera. SISPI is implemented as a distributed multi-processor system with a software architecture based on the Client-Server and Publish-Subscribe design patterns. The underlying message passing protocol is based on PYRO, a powerful distributed object technology system written entirely in Python. A distributed shared variable system was added to support exchange of telemetry data and other information between different components of the system. We discuss the SISPI infrastructure software, the image pipeline, the observer console and user interface architecture, image quality monitoring, the instrument control system, and the observation strategy tool.

The BigBOSS experiment is a proposed DOE-NSF Stage IV dark energy survey. The all sky survey will be used to study the baryon acoustic oscillation (BAO) and growth of large scale structure from 0.2 < z < 3.5. Key to the timely success of BigBOSS is the total optical throughput of the system. The guide, focus/alignment system will provide essential pointing information, eld acquisition, atmospheric monitoring and alignment corrections all used to maximize light throughput.

A mission critical goal of the JDEM mission is to resolve distant galaxies both optically and spectroscopically. In order to achieve this goal, the spacecraft must make observations at the diffraction limit. A full scale attitude control testbed was developed to determine the ability of preliminary designs to meet stringent attitude control requirements. We demonstrate our ability to control a realistic spacecraft structure to ~20 mas. Expected reaction wheel feedback effects are observed and mitigation discussed.

Monitoring the aerosol component of the lowest 10 km of the atmosphere at UV wavelengths (300 - 400 nm) is an important part of the High Resolution Fly's Eye astrophysics experiment. Our method of atmospheric monitoring uses a frequency tripled YAG laser and a steering system that can point the beam anywhere in the sky. The same detector that measures scintillation light from high energy cosmic rays also measures light scattered from this laser system over a range of laser energies, geometries, and polarizations. This paper describes the technique, the laser system, and some recent measurements.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.