The One Degree Imager (ODI) was deployed during the summer of 2012 at the WIYN 3.5m telescope, located on Kitt Peak near Tucson, AZ (USA). ODI is an optical imager designed to deliver atmosphere-limited image quality (≤ 0.4” FWHM) over a one degree field of view, and uses Orthogonal Transfer Array (OTA) detectors to also allow for on-chip tip/tilt image motion compensation. At this time, the focal plane is partially populated (”pODI”) with 13 out of 64 OTA detectors, providing a central scientifically usable field of view of about 24′ x 24′; four of the thirteen detectors are installed at outlying positions to probe image quality at all field angles. The image quality has been verified to be indeed better than 0.4′′ FWHM over the full field when atmospheric conditions allow. Based on over one year of operations, we summarize pODIs performance and lessons learned. As pODI has proven the viability of the ODI instrument, the WIYN consortium is engaging in an upgrade project to add 12 more detectors to the focal plane enlarging the scientifically usable field of view to about 40′ x 40′. A design change in the new detectors has successfully addressed a low light level charge transfer inefficiency.
We describe the design, construction and measured performance of the Kitt Peak Ohio State Multi-Object Spectrograph
(KOSMOS) for the 4-m Mayall telescope and the Cerro Tololo Ohio State Multi-Object Spectrograph (COSMOS) for
the 4-m Blanco telescope. These nearly identical imaging spectrographs are modified versions of the OSMOS
instrument; they provide a pair of new, high-efficiency instruments to the NOAO user community. KOSMOS and
COSMOS may be used for imaging, long-slit, and multi-slit spectroscopy over a 100 square arcminute field of view with
a pixel scale of 0.29 arcseconds. Each contains two VPH grisms that provide R~2500 with a one arcsecond slit and their
wavelengths of peak diffraction efficiency are approximately 510nm and 750nm. Both may also be used with either a
thin, blue-optimized CCD from e2v or a thick, fully depleted, red-optimized CCD from LBNL. These instruments were
developed in response to the ReSTAR process. KOSMOS was commissioned in 2013B and COSMOS was
commissioned in 2014A.
The OSIRIS-REx asteroid sample return mission carries a suite of three cameras referred to as OCAMS. The Space
Dynamics Laboratory (SDL) at Utah State University is providing the CCD-based detector assemblies for OCAMS to
the Lunar Planetary Lab (LPL) at the University of Arizona. Working with the LPL, SDL has designed the electronics to
operate a 1K by 1K frame transfer Teledyne DALSA Multi-Pinned Phase (MPP) CCD. The detector assembly
electronics provides the CCD clocking, biasing, and digital interface with the OCAMS payload Command Control
Module (CCM). A prototype system was built to verify the functionality of the detector assembly design and to
characterize the detector system performance at the intended operating temperatures. The characterization results are
described in this paper.
A project is currently underway to upgrade the Kitt Peak National Observatory (KPNO) Mosaic-1 Imager, an 8192 x
8192 pixel CCD array used on the Mayall 4-meter and WIYN 0.9-meter telescopes. Mosaic-1 has been a heavily
subscribed instrument by the US astronomical community since it was commissioned more than a decade ago. In recent
years, however, the reliability and efficiency of Mosaic-1 has declined due to aging and failing components. In addition,
servicing has become more and more difficult as spare parts are used up, replacement parts become unavailable, and
technical expertise for the out-dated controller technology diminishes. The Mosaic-1 upgrade project addresses these
reliability and servicing concerns by replacing the CCDs with modern detectors and replacing the controllers with a
MONSOON image acquisition system. The upgrade will also enhance the scientific productivity of the instrument
through reduced read times, lower read noise, and improved quantum efficiency. We will describe the project status, the
technical requirements related to the installation of new CCD detectors and MONSOON controllers, the configuration of
the system, and integration of the system into the existing instrument and telescope environments.
KEYWORDS: Sensors, Charge-coupled devices, Power supplies, Analog electronics, Signal detection, Control systems, Electronics, Clocks, Detector development, Calibration
The Torrent detector control system is being developed at NOAO as a follow-on to the MONSOON systems that
have been used successfully for instruments at several institutions. The poster will cover the evolution of
MONSOON into Torrent and will cover: Motivations, What's gained/What's lost, Major Technological Differences,
Goals, plans and first users.
KEYWORDS: Sensors, Control systems, Calibration, Field programmable gate arrays, Signal detection, Analog electronics, Mirrors, Clocks, Connectors, Power supplies
The MONSOON Torrent image Acquisition system is being designed partially to reduce the complexity in
configuring a Detector controller system. This paper will discuss how we have achieved this goal by creating a system
of automation for the configuration task. We also discuss how the automated systems work to insure proper focal plane
operation in the face of potential network, communications and controller hardware failures during observing sessions.
The Torrent hardware design is discussed in section 2. In Sections 4 and 5 we discuss the automated processes used
to develop the description of the Torrent hardware used by the rest of the automation system. In Sections 6 through 8 we
discuss the semi automated system configuration/integration/design software. In Section 9 we present the automated
run-time configuration tools and discuss how it operates in the face of various failures. In Section 10 we discuss how
Torrent and the automated systems will achieve the goal of reducing observing down time in the face of hardware
failures.
The MONSOON Detector Controller has successfully demonstrated the ability to control the complex image acquisition
and real time processing required to achieve quality science performance from the Orthogonal Transfer Array (OTA)
detector technology. A mosaic of four OTA detectors has been used to track multiple guide stars and apply charge shift
corrections to compensate for real time image motion. The control algorithms required to achieve this have been
embedded and distributed within the MONSOON controller to reduce the control loop latency and improve correction
efficiency. This paper highlights the flexibility of the MONSOON architecture in supporting the many roles required by
applications of scientific detectors.
KEYWORDS: Mirrors, Actuators, Telescopes, Active optics, Control systems, Computer programming, Systems modeling, Adaptive optics, Monochromatic aberrations, Thirty Meter Telescope
The Thirty Meter Telescope (TMT) project is a partnership between ACURA, AURA, Caltech, and the University of California. The design calls for a 3.6 m diameter secondary mirror and an elliptical tertiary mirror measuring more than 4 m along its major axis. Each mirror will weigh more than two metric tons and must be articulated to compensate for deformation of the telescope structure. The support and control of these "smaller optics" pose significant challenges for
the designers. We present conceptual designs for active and passive figure control and articulation of these optics.
The Thirty Meter Telescope (TMT) will utilize adaptive optics to achieve near diffraction-limited images in the near-infrared using both natural and laser guide stars. The Laser Guide Star Facility (LGSF) will project up to eight Na laser beacons to generate guide stars in the Earth's Na layer at 90 - 110 km altitude. The LGSF will generate at least four distinct laser guide star patterns (asterisms) of different geometry and angular diameter to meet the requirements of the specific adaptive optics modules for the TMT instruments. We describe the baseline concept for this facility, which draws on the heritage from the systems being installed at the Gemini telescopes. Major subsystems include the laser itself and its enclosure, the optics for transferring the laser beams up the telescope structure and the asterism generator and launch telescope, both mounted behind the TMT secondary mirror. We also discuss operational issues, particularly the required safety interlocks, and potential future upgrades to higher laser powers and precompensation of the projected laser beacons using an uplink adaptive optics system.
In this paper, we provide an overview of the adaptive optics (AO) program for the Thirty Meter Telescope (TMT) project, including an update on requirements; the philosophical approach to developing an overall AO system architecture; the recently completed conceptual designs for facility and instrument AO systems; anticipated first light capabilities and upgrade options; and the hardware, software, and controls interfaces with the remainder of the observatory. Supporting work in AO component development, lab and field tests, and simulation and analysis is also discussed. Further detail on all of these subjects may be found in additional papers in this conference.
The NEWFIRM program will provide a widefield IR imaging system optimized for survey programs on the NOAO 4-m telescopes in Arizona and Chile. The camera images a 28 x 28 arcminute field of view over 1-2.4 microns wavelength range with a 4K x 4K pixel array mosaic. We present an overview of camera design features including optics design, manufacture, and mounting; control of internal flexure between input and output focal planes; mosaic array mount design; and thermal design. We also discuss the status of other projects within the program: array control electronics, observation and pipeline reduction software, and production of the science grade array complement. The program is progressing satisfactorily and we expect to deliver the system to the northern 4-m telescope in 2005.
The advent of large focal planes requiring many signal channels has exacerbated the problems associated with guaranteeing detector controller performance. The performance specifications for large focal plane controllers includes both 'per channel' requirements such as noise, linearity, dynamic range, etc. and 'system' requirements such as channel cross talk, gain matching, etc. To assess these performance parameters and fully characterize the controller before integration to a focal plane, the MONSOON team has adopted a testing methodology that is based on industry standard practices. This adoption has provided a consistent testing method that produces repeatable results and allows full characterization of the controller performance. This approach will provided a tool to assist in predicting focal plane performance before integration and establishes base line performance values for subsequent detector optimization efforts.
The adaptive optics system for the Gemini South telescope, currently in the design phase, consists of several major subsystem. The largest subsystem, called the AO module, contains most of the optics and electronics and is mounted on one of the Cassegrain instrument ports. The initial system will be a conventional laser guide star AO system, but the plan is to eventually expand it to a multi-conjugate system. The system is being designed to readily add the components necessary to upgrade to a multi-conjugate system. This paper describes the design challenges encountered and solutions that were derived for the AO module design. The complexity of the multi-conjugate version is illustrated, including optical, mechanical, electronic and controls issues.
The multi-conjugate adaptive optics (MCAO) system design for the Gemini-South 8-meter telescope will provide near-diffraction-limited, highly uniform atmospheric turbulence compensation at near-infrared wavelengths over a 2 arc minute diameter field-of-view. The design includes three deformable mirrors optically conjugate to ranges of 0, 4.5, and 9.0 kilometers with 349, 468, and 208 actuators, five 10-Watt-class sodium laser guide stars (LGSs) projected from a laser launch telescope located behind the Gemini secondary mirror, five Shack-Hartmann LGS wavefront sensors of order 16 by 16, and three tip/tilt natural guide star (NGS) wavefront sensors to measure tip/tilt and tilt anisoplanatism wavefront errors. The WFS sampling rate is 800 Hz. This paper provides a brief overview of sample science applications and performance estimates for the Gemini South MCAO system, together with a summary of the performance requirements and/or design status of the principal subsystems. These include the adaptive optics module (AOM), the laser system (LS), the beam transfer optics (BTO) and laser launch telescope (LLT), the real time control (RTC) system, and the aircraft safety system (SALSA).
The Gemini Observatory is planning to implement a Multi Conjugate Adaptive Optics System as a facility instrument for the Gemini-South telescope. The system will include 5 Laser Guide Stars, 3 Natural Guide Stars, and 3 Deformable mirrors optically conjugated at different altitudes to achieve near-uniform atmospheric compensation over a 1 arc minute square field of view. The control of such a system will be split in 3 main functions: the control of the opto- mechanical assemblies of the whole system (including the Laser, the Beam Transfer Optics and the Adaptive Optics bench), the control of the Adaptive Optics System itself at a rate of 800 frames per second and the control of the safety system. The control of the adaptive Optics System is the most critical in terms of real time performance. In this paper, we will describe the requirements for the whole Multi Conjugate Adaptive Optica Control System, preliminary designs for the control of the opto-mechanical devices and architecture options for the control of the Adaptive Optics system and the safety system.
A new adaptive optics system has been constructed for moderately high resolution in the near infrared at the Multiple Mirror Telescope (MMT). The system, called FASTTRAC II, has been designed to combine the highest throughput with the lowest possible background emission by making the adaptive optical element be an existing and necessary part of the telescope, and by eliminating all warm surfaces between the telescope and the science camera's dewar. At present, only natural guide stars are supported, but by the end of 1995, we will add the capability to use a single sodium resonance beacon derived from a laser beam projected nearly coaxially with the telescope. In this paper, we present a description of FASTTRAC II, and show results from its first test run at the telescope in April 1995.
KEYWORDS: Control systems, Temperature metrology, Mirrors, Glasses, Astronomy, Computing systems, Electronics, Servomechanisms, Annealing, Control systems design
The process for spincasting 8 meter borosilicate honeycomb mirrors requires us to heat 14 tons of glass in a complex mold to 1170 °C while spinning the entire furnace at 6.8 rpm. After casting, the honeycomb blank must be cooled through the annealing temperature range at 0.2 °C per hour. The glass will be in the furnace for an eight week period. We describe here the computer control system to read the 600 N-type thermocouples and control the 270 8-kilowatt heaters used in the spincasting furnace. The control system uses a proportional — integral — derivative (PID) algorithm to regulate the furnace temperature to a few degrees over the entire casting cycle. Considerable design effort has gone into assuring that a component failure or a control system error does not turn an 8 meter nilrror into an expensive patio ornament. Errors are avoided by four strategic steps: fault avoidance, fault detection, fault containment and fault recovery. Examples are provided in each of these categories. System redundancy begins with three on-board 68000-family VME-bus computers which control overlapping areas of the furnace. Redundancy extends down through the temperature measurement and power control systems with many modular, interleaved, and optically isolated subsystems. Data logging and system monitoring are achieved with a Sun 3/280 workstation running IRAF in the control room. Rotation of the furnace is controlled by two 40 HP DC servomotors with speed regulation to 0.1%. The oven control system contains over 300 circuit cards, dozens of subracks and power supplies, more than 3000 connectors of at least 10 different types. there are more than 20 miles of wire and cable, most with multiple conductors, ranging from fiber optics thinner than a hair to power cables more than an inch thick. Results are presented from a subset of this control system which has been used to cast three 3.5 meter honeycomb mirrors in 1.988 and 1989.
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