A next-generation instrument named, Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES), is being planned for the W. M. Keck Observatory. SCALES will have an integral field spectrograph (IFS) and a diffraction-limited imaging channel to discover and spectrally characterize the directly imaged exoplanets. Operating at thermal infrared wavelengths (1-5 μm, and a goal of 0.6-5 μm), the imaging channel of the SCALES is designed to cover a 12′′ × 12′′ field of view with low distortions and high throughput. Apart from expanding the mid-infrared science cases and providing a potential upgrade/alternative for the NIRC2, the H2RG detector of the imaging channel can take high-resolution images of the pupil to aid the alignment process. Further, the imaging camera would also assist in small field acquisition for the IFS arm. In this work, we present the optomechanical design of the imager and evaluate its capabilities and performances.
We present the design of SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy) a new 2-5 micron coronagraphic integral field spectrograph under construction for Keck Observatory. SCALES enables low-resolution (R∼50) spectroscopy, as well as medium-resolution (R∼4,000) spectroscopy with the goal of discovering and characterizing cold exoplanets that are brightest in the thermal infrared. Additionally, SCALES has a 12x12” field-of-view imager that will be used for general adaptive optics science at Keck. We present SCALES’s specifications, its science case, its overall design, and simulations of its expected performance. Additionally, we present progress on procuring, fabricating and testing long lead-time components.
Since the start of science operations in 1993, the twin 10-meter W. M. Keck Observatory (WMKO) telescopes have continued to maximize their scientific impact and to produce transformative discoveries that keep the observing community on the frontiers of astronomical research. Upgraded capabilities and new instrumentation are provided though collaborative partnerships with Caltech, the University of California, and the University of Hawaii instrument development teams, as well as industry and other organizations. This paper summarizes the performance of recently commissioned infrastructure projects, technology upgrades, and new additions to the suite of observatory instrumentation. We also provide a status of projects currently in design or development phases and, since we keep our eye on the future, summarize projects in exploratory phases that originate from our 2022 strategic plan developed in collaboration with our science community to adapt and respond to evolving science needs.
We present a compact, double-pass cross-dispersed echelle spectrograph that is tailored specifically to cover the 383 nm to 403 nm spectral range and record R∼16,000 spectra of the stellar chromospheric Ca II H and K lines. This ‘H and K’ spectrometer was developed as a subsystem of the Keck Planet Finder (KPF), which is an extremely precise optical (440 - 870 nm) radial velocity spectrograph for Keck I, scheduled for commissioning Fall 2022, with the science objective of measuring precise masses of exoplanets. The H and K spectrometer will observe simultaneously with KPF to independently track the chromospheric activity of the host stars that KPF observes, which is expected to dominate the KPF measurement floor over long timescales. The H and K Spectrometer is fiber fed from the KPF fiber injection unit with total throughput of 4-7% (top of telescope to CCD) over its operating spectral range. Here we detail the optical design trade offs, mechanical design, and first results from alignment and integration testing.
We present preliminary laboratory cryogenic test results for the Coronagraph Slide mechanism, which allows observers the choice of up to 4 coronagraphic focal plane masks when using SCALES (Santa Cruz Array of Lenslets for Exoplanet Spectroscopy). SCALES is a 2-5 micron high-contrast lenslet integral field spectrograph currently undergoing preliminary design for the W. M. Keck Observatory. When deployed behind the Keck Adaptive Optics system, SCALES will be used to detect and characterize a wide variety of exoplanets. To minimize thermal emission, all optical and mechanical components of SCALES are fully cryogenic. The Coronagraph Slide is the first fully cryogenic mechanism for SCALES designed, built, and tested in-house at UCSC with mostly off-the-shelf components.
KEYWORDS: Exoplanets, Planets, Spectrographs, Analog electronics, Solar system, Galactic astronomy, Signal to noise ratio, Telescopes, Observatories, Integrating spheres
Exoplanets are abundant in our galaxy and yet characterizing them remains a technical challenge. Solar System planets provide an opportunity to test the practical limitations of exoplanet observations with high signal-to-noise data that we cannot access for exoplanets. However, data on Solar System planets differ from exoplanets in that Solar System planets are spatially resolved while exoplanets are unresolved point-sources. We present a novel instrument designed to observe Solar System planets as though they are exoplanets, the Planet as Exoplanet Analog Spectrograph (PEAS). PEAS consists of a dedicated 0.5-m telescope and off-the-shelf optics, located at Lick Observatory. PEAS uses an integrating sphere to disk-integrate light from the Solar System planets, producing spatially mixed light more similar to the spectra we can obtain from exoplanets. This paper describes the general system design and early results of the PEAS instrument.
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. KPF is designed to characterize exoplanets via Doppler spectroscopy with a goal of a single measurement precision of 0.3 m s-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. Here we provide post-preliminary design review design updates for several subsystems, including: the main spectrometer, the fabrication of the Zerodur optical bench; the data reduction pipeline; fiber agitator; fiber cable design; fiber scrambler; VPH testing results and the exposure meter.
SCALES (Santa Cruz Array of Lenslets for Exoplanet Spectroscopy) is a 2-5 micron high-contrast lenslet integral-field spectrograph (IFS) driven by exoplanet characterization science requirements and will operate at W. M. Keck Observatory. Its fully cryogenic optical train uses a custom silicon lenslet array, selectable coronagraphs, and dispersive prisms to carry out integral field spectroscopy over a 2.2 arcsec field of view at Keck with low (< 300) spectral resolution. A small, dedicated section of the lenslet array feeds an image slicer module that allows for medium spectral resolution (5000 10000), which has not been available at the diffraction limit with a coronagraphic instrument before. Unlike previous IFS exoplanet instruments, SCALES is capable of characterizing cold exoplanet and brown dwarf atmospheres (< 600 K) at bandpasses where these bodies emit most of their radiation while capturing relevant molecular spectral features.
The new deployable tertiary mirror for the Keck I telescope (K1DM3) at the W. M. Keck Observatory has been assembled, tested and shipped to the telescope site, and is currently being installed. The mirror is capable of reflecting the beam to one of six positions around the telescope elevation ring or to retract out of the way to allow the use of Cassegrain instruments. This new functionality is intended to allow rapid instrument changes for transient event observations and improve telescope operations. This paper presents the final as-built design. Additionally, this paper presents detailed information about our alignment approach in the attempt to duplicate the instrument pointing orientation of the existing M3.
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development for the W.M. Keck Observatory. The instrument recently passed its preliminary design review and is currently in the detailed design phase. KPF is designed to characterize exoplanets using Doppler spectroscopy with a single measurement precision of 0.5 m s−1 or better; however, its resolution and stability will enable a wide variety of other astrophysical pursuits. KPF will have a 200 mm collimated beam diameter and a resolving power greater than 80,000. The design includes a green channel (445 nm to 600 nm) and red channel (600 nm to 870 nm). A novel design aspect of KPF is the use of a Zerodur optical bench, and Zerodur optics with integral mounts, to provide stability against thermal expansion and contraction effects.
The Automated Planet Finder (APF) at Lick Observatory on Mount Hamilton is a modern 2.4 meter computer controlled telescope. At one Nasmyth focus is the Levy Spectrometer, at present the sole instrument used with the APF. The primary research mission of the APF and the Levy Spectrometer is high-precision Doppler spectroscopy. Observing at the APF is unattended; custom software written by diverse authors in diverse languages manage all aspects of a night’s observing.
This paper will cover some of the key software architecture decisions made in the development of autonomous observing at the APF. The relevance to future projects of these decisions will be emphasized throughout.
The Automated Planet Finder (APF) was originally designed as a single purpose facility to search for exoplanets. The APF, however, has become a general use observatory that is used by astronomers the world over. We describe the improvements to our software for operations that both optimize finding planets with known periods and supporting a much broader community of astronomers with a variety of interests and requirements. These include a variety of observing modes beyond the originally envisioned fixed target lists, such as time dependent priorities to meet the needs of rapid varying targets, and improved tools for simulating observing cadence for the planet hunting teams. We discuss the underlying software for the APF, illustrating why its simplicity of use allows users to write software that focuses on scientific productivity. Because of this simplicity, we can then develop scheduling software, which is easily integrated into the APF operations suite. We test these new scheduling modes using a nightly simulator which uses historical weather and seeing data. After discussing this new simulation tool, we measure how well the methods work after a 36 month simulated campaign to follow-up transiting targets. We find that the data yield of each of the tested schemes is similar. Therefore, we can focus on the best potential scientific return with little concern about the impact on the number or duration of observations.
KEYWORDS: Mirrors, Telescopes, Astronomy, Calibration, Sensors, Distortion, Data modeling, Spectroscopy, James Webb Space Telescope, Magnetic resonance imaging
Motivated by the ever increasing pursuit of science with the transient sky (dubbed Time Domain Astronomy or TDA), we are fabricating and will commission a new deployable tertiary mirror for the Keck I telescope (K1DM3) at the W.M. Keck Observatory. This paper presents the detailed design of K1DM3 with emphasis on the opto- mechanics. This project has presented several design challenges. Foremost are the competing requirements to avoid vignetting the light path when retracted against a sufficiently rigid system for high-precision and repeatable pointing. The design utilizes an actuated swing arm to retract the mirror or deploy it into a kinematic coupling. The K1DM3 project has also required the design and development of custom connections to provide power, communications, and compressed air to the system. This NSF-MRI funded project is planned to be commissioned in Spring 2017.
We report initial performance results emerging from 600 h of observations with the Automated Planet Finder (APF) telescope and Levy spectrometer located at UCO/Lick Observatory. We have obtained multiple spectra of 80 G, K, and M-type stars, which comprise 4954 individual Doppler radial velocity (RV) measurements with a median internal uncertainty of 1.35 ms−1. We find a strong, expected correlation between the number of photons accumulated in the 5000 to 6200 Å iodine region of the spectrum and the resulting internal uncertainty estimates. Additionally, we find an offset between the population of G and K stars and the M stars within the dataset when comparing these parameters. As a consequence of their increased spectral line densities, M-type stars permit the same level of internal uncertainty with 2× fewer photons than G-type and K-type stars. When observing M stars, we show that the APF/Levy has essentially the same speed-on-sky as Keck/high resolution echelle spectrometer (HIRES) for precision RVs. In the interest of using the APF for long-duration RV surveys, we have designed and implemented a dynamic scheduling algorithm. We discuss the operation of the scheduler, which monitors ambient conditions and combines on-sky information with a database of survey targets to make intelligent, real-time targeting decisions.
By July 2014, the Automated Planet Finder (APF) at Lick Observatory on Mount Hamilton will have completed its first year of operation. This facility combines a modern 2.4m computer-controlled telescope with a flexible development environment that enables efficient use of the Levy Spectrometer for high cadence observations. The Levy provides both sub-meter per second radial velocity precision and high efficiency, with a peak total system throughput of 24%. The modern telescope combined with efficient spectrometer routinely yields over 100 observations of 40 stars in a single night, each of which has velocity errors of 0.7 to 1.4 meters per second, all with typical seeing of < 1 arc second full-width-half-maximum (FWHM). The whole observing process is automated using a common application programming interface (API) for inter-process communication which allows scripting to be done in a variety of languages (Python, Tcl, bash, csh, etc.) The flexibility and ease-of-use of the common API allowed the science teams to be directly involved in the automation of the observing process, ensuring that the facility met their requirements. Since November 2013, the APF has been routinely conducting autonomous observations without human intervention.
The University of California Observatories will design and construct a deployable tertiary mirror (named K1DM3) for the Keck 1 telescope, which will complement technical and scientific advances in the area of time-domain astronomy. The K1DM3 device will enable astronomers to swap between any of the foci on Keck 1 in under 2 minutes, both to monitor varying sources (e.g. stars orbiting the Galactic center) and catch rapidly fading sources (e.g. supernovae, flares, gamma-ray bursts). In this paper, we report on the design development during our in-progress Preliminary Design phase. The design consists of a passive wiffle tree axial support system and a diaphragm lateral support system with a 5 arcminute field-of-view mirror. The mirror assembly is inserted into the light path with an actuation system and it relies on a kinematic mechanism for achieving repeatable, precise positioning. This project, funded by an NSF MRI grant, aspires to complete by the end of 2016.
We describe the design and first-light early science performance of the Shane Adaptive optics infraRed Camera- Spectrograph (ShARCS) on Lick Observatory’s 3-m Shane telescope. Designed to work with the new ShaneAO adaptive optics system, ShARCS is capable of high-efficiency, diffraction-limited imaging and low-dispersion grism spectroscopy in J, H, and K-bands. ShARCS uses a HAWAII-2RG infrared detector, giving high quantum efficiency (<80%) and Nyquist sampling the diffraction limit in all three wavelength bands. The ShARCS instrument is also equipped for linear polarimetry and is sensitive down to 650 nm to support future visible-light adaptive optics capability. We report on the early science data taken during commissioning.
A Cassegrain mounted adaptive optics instrument presents unique challenges for opto-mechanical design. The flexure and temperature tolerances for stability are tighter than those of seeing limited instruments. This criteria requires particular attention to material properties and mounting techniques. This paper addresses the mechanical designs developed to meet the optical functional requirements. One of the key considerations was to have gravitational deformations, which vary with telescope orientation, stay within the optical error budget, or ensure that we can compensate with a steering mirror by maintaining predictable elastic behavior. Here we look at several cases where deformation is predicted with finite element analysis and Hertzian deformation analysis and also tested. Techniques used to address thermal deformation compensation without the use of low CTE materials will also be discussed.
A new high-order adaptive optics system is now being commissioned at the Lick Observatory Shane 3-meter telescope in California. This system uses a high return efficiency sodium beacon and a combination of low and high-order deformable mirrors to achieve diffraction-limited imaging over a wide spectrum of infrared science wavelengths covering 0.8 to 2.2 microns. We present the design performance goals and the first on-sky test results. We discuss several innovations that make this system a pathfinder for next generation AO systems. These include a unique woofer-tweeter control that provides full dynamic range correction from tip/tilt to 16 cycles, variable pupil sampling wavefront sensor, new enhanced silver coatings developed at UC Observatories that improve science and LGS throughput, and tight mechanical rigidity that enables a multi-hour diffraction-limited exposure in LGS mode for faint object spectroscopy science.
The Event Monitor and Incident Response system (emir) is a flexible, general-purpose system for monitoring
and responding to all aspects of instrument, telescope, and general facility operations, and has been in use at the
Automated Planet Finder telescope for two years. Responses to problems can include both passive actions (e.g.
generating alerts) and active actions (e.g. modifying system settings). Emir includes a monitor-and-response
daemon, plus graphical user interfaces and text-based clients that automatically configure themselves from data
supplied at runtime by the daemon. The daemon is driven by a configuration file that describes each condition
to be monitored, the actions to take when the condition is triggered, and how the conditions are aggregated into
hierarchical groups of conditions. Emir has been implemented for the Keck Task Library (KTL) keyword-based
systems used at Keck and Lick Observatories, but can be readily adapted to many event-driven architectures.
This paper discusses the design and implementation of Emir , and the challenges in balancing the competing
demands for simplicity, flexibility, power, and extensibility.
Emir ’s design lends itself well to multiple purposes, and in addition to its core monitor and response functions,
it provides an effective framework for computing running statistics, aggregate values, and summary state values
from the primitive state data generated by other subsystems, and even for creating quick-and-dirty control loops
for simple systems.
It is very common to write device drivers and code that access low level operation system functions in C or C+
+. There are also many powerful C and C++ libraries available for a variety of tasks. Java is a programming language
that is meant to be system independent and is arguably much simpler to code than C/C++. However, Java has minimal
support for talking to native libraries, which results in interesting challenges when using C/C++ libraries with Java code.
Part of the problem is that Java's standard mechanism for communicating with C libraries, Java Native Interface,
requires a significant amount of effort to do fairly simple things, such as copy structure data from C to a class in Java.
This is largely solved by using the Java Native Access Library, which provides a reasonable way of transferring data
between C structures and Java classes and calling C functions from Java. A more serious issue is that there is no
mechanism for a C/C++ library loaded by a Java program to call a Java function in the Java program, as this is a major
issue with any library that uses callback functions. A solution to this problem was found using a moderate amount of C
code and multiple threads in Java. The Keck Task Language API (KTL) is used as a primary means of inter-process
communication at Keck and Lick Observatory. KTL is implemented in a series or C libraries and uses callback functions
for asynchronous communication. It is a good demonstration of how to use a C library within a Java program.
KEYWORDS: Databases, Observatories, Camera shutters, Data storage, Telecommunications, Telescopes, Binary data, Switches, Temperature metrology, Space telescopes
This paper discusses Lick Observatory's local solution for retaining a complete history of everything. Leveraging
our existing deployment of a publish/subscribe communications model that is used to broadcast the state of all
systems at Lick Observatory, a monitoring daemon runs on a dedicated server that subscribes to and records
all published messages. Our success with this system is a testament to the power of simple, straightforward
approaches to complex problems. The solution itself is written in Python, and the initial version required about
a week of development time; the data are stored in PostgreSQL database tables using a distinctly simple schema.
Over time, we addressed scaling issues as the data set grew, which involved reworking the PostgreSQL
database schema on the back-end. We also duplicate the data in flat files to enable recovery or migration of the
data from one server to another. This paper will cover both the initial design as well as the solutions to the
subsequent deployment issues, the trade-offs that motivated those choices, and the integration of this history
database with existing client applications.
The University of California (UC) began operating the Lick Observatory onMount Hamilton, California in 1888. Nearly a
century later, UC became a founding partner in the establishment of theW. M. Keck Observatory (WMKO) in Hawaii, and
it is now a founding partner in the Thirty Meter Telescope (TMT) project. Currently, most UC-affiliated observers conduct
the majority of their ground-based observations using either the Keck 10-meter Telescopes on Mauna Kea or one or more
of the six Lick telescopes now in operation on Mount Hamilton; some use both the Keck and Lick Telescopes. Within the
next decade, these observers should also have the option of observing with the TMT if construction proceeds on schedule.
During the current decade, a growing fraction of the observations on both the Keck and Lick Telescopes have been
conducted from remote observing facilities located at the observer's home institution; we anticipate that TMT observers
will expect the same. Such facilities are now operational at 8 of the 10 campuses of UC and at the UC-operated Lawrence
Berkeley National Laboratory (LBNL); similar facilities are also operational at several other Keck-affiliated institutions.
All of the UC-operated remote observing facilities are currently dual-use, supporting remote observations with either the
Keck or Lick Telescopes.
We report on our first three years of operating such dual-use facilities and describe the similarities and differences
between the Keck and Lick remote observing procedures. We also examine scheduling issues and explore the possibility
of extending these facilities to support TMT observations.
A successful instrument or telescope will measure its productive lifetime in decades;
over that period, the technology behind the control hardware and software will evolve, and be
replaced on a per-component basis. These new components must successfully integrate with
the old, and the difficulty of that integration depends strongly on the design decisions made
over the course of the facility's history. The same decisions impact the ultimate success of each
upgrade, as measured in terms of observing efficiency and maintenance cost.
We offer a case study of these critical design decisions, analyzing the layers of software
deployed for instruments under the care of UCO/Lick Observatory, including recent upgrades
to the Low Resolution Imaging Spectrometer (LRIS) at Keck Observatory in Hawaii, as well
as the Kast spectrograph, Lick Adaptive Optics system, and Hamilton spectrograph, all at Lick
Observatory's Shane 3-meter Telescope at Mt. Hamilton.
These issues play directly into design considerations for the software intended for use at
the next generation of telescopes, such as the Thirty Meter Telescope. We conduct our analysis
with the future of observational astronomy infrastructure firmly in mind.
A mosaic of two 2k x 4k fully depleted, high resistivity CCD
detectors was installed in the red channel of the Low Resolution
Imaging Spectrograph for the Keck-I Telescope in June, 2009 replacing
a monolithic Tektronix/SITe 2k x 2k CCD. These CCDs were fabricated
at Lawrence Berkeley National Laboratory (LBNL) and packaged and
characterized by UCO/Lick Observatory. Major goals of the detector
upgrade were increased throughput and reduced interference fringing
at wavelengths beyond 800 nm, as well as improvements in the
maintainability and serviceability of the instrument. We report on
the main features of the design, the results of optimizing detector
performance during integration and testing, as well as the
throughput, sensitivity and performance of the instrument as
characterized during commissioning.
Poco, short for Pointing Control, is a modern telescope control system for use with the telescopes at Lick
Observatory. It is currently in use with the Shane 3-meter and Nickel 1-meter telescopes. It may also be used with other
telescopes in the future. The software is designed to be very reliable, accurate, flexible, and full featured while still being
very easy to use. It needs to communicate with other systems such as auto-guiders, instruments, remote observing
watchdogs, and possible robotic control.
The telescopes use motor systems installed in the 1970's. Upgrading to modern servo motors was not practical,
so the telescopes use their stepper motors for fine motor control while switching to much larger and less accurate motors
for large moves. It requires a variety of techniques to quickly and smoothly reach target locations and maintain tracking.
The software achieves these goals, overcoming the significant hardware limitations of these older telescope
using mostly off the shelf hardware. This paper will describe the more interesting aspects of the system such as locating
objects from catalog coordinates, motor control algorithms, user interfaces, communications between systems, and
software architecture.
We describe a project to enable remote observing on the Nickel 1-meter Telescope at Lick Observatory. The purpose
was to increase the subscription rate and create more economical means for graduate- and undergraduate students to
observe with this telescope. The Nickel Telescope resides in a 125 year old dome on Mount Hamilton. Remote
observers may work from any of the University of California (UC) remote observing facilities that have been created to
support remote work at both Keck Observatory and Lick Observatory.
The project included hardware and software upgrades to enable computer control of all equipment that must be operated
by the astronomer; a remote observing architecture that is closely modeled on UCO/Lick's work to implement remote
observing between UC campuses and Keck Observatory; new policies to ensure safety of Observatory staff and
equipment, while ensuring that the telescope subsystems would be suitably configured for remote use; and new software
to enforce the safety-related policies.
The results increased the subscription rate from a few nights per month to nearly full subscription, and has spurred the
installation of remote observing sites at more UC campuses. Thanks to the increased automation and computer control,
local observing has also benefitted and is more efficient. Remote observing is now being implemented for the Shane 3-
meter telescope.
Web-enabled user interfaces for the control and monitoring of instruments and telescopes have a checkered
history. However, the remarkable interactive speed and quality of Google Maps and Google Suggests have led us,
like others, to take another look at implementing services over the Web. The so-called AJAX mechanism enables
simple, lightweight, efficient, and responsive interfaces in nearly any modern Web browser. We discuss methods,
security, and other implementation issues for sample interfaces that include telescope monitoring, instrument
control, and weather station information.
The majority of extra-solar planets discovered to date have been found using Doppler-shift measurements obtained with the Hamilton Spectrometer at Lick Observatory and the High Resolution Echelle Spectrometer (HIRES) at Keck Observatory. Each of these spectrometers employs an integral exposure meter which enables observers to optimize exposure times so as to achieve the required signal-to-noise and to determine the photon-weighted midpoint of each science exposure (which is needed to correct the Doppler shift to the Solar System barycenter). In both of these systems, a propeller mirror located behind the spectrometer slit picks off a few percent of the light and directs it to a photo-multiplier tube (PMT) used to measure the exposure level versus time. In late 2006, the new Automated Planet Finder (APF) Telescope and APF Spectrometer are scheduled to begin operations at Lick Observatory; both will be dedicated exclusively to the search for extra-solar planets. Like the Hamilton and HIRES Spectrometers, the APF Spectrometer will employ an integral exposure meter, but one with a significantly different design. The APF exposure meter will employ a stationary pellicle located ahead of the slit to pick off 4% of the light and direct it to the guide camera. That camera will produce images typically at a 1 Hz rate, and those images will be used both for autoguiding and for computing the exposure level delivered to the spectrometer. In each guide camera image obtained during a science exposure, the time-tagged signal from the pixels that correspond to the spectrometer slit will be integrated in software to determine the current exposure level and the photon-weighted midpoint of that science exposure. We compare these two different design approaches, and describe the significant hardware and software features of each of these systems.
The DEIMOS spectrograph is a multi-object spectrograph being built for Keck II. DEIMOS was delivered in February 2002, became operational in May, and is now about three-quarters of the way through its commissioning period. This paper describes the major problems encountered in completing the spectrograph, with particular emphasis on optical quality and image motion. The strategies developed to deal with these problems are described. Overall, commissioning is going well, and it appears that DEIMOS will meet all of its major performance goals.
KEYWORDS: Computer programming, Telescopes, Control systems, Switches, Computer architecture, Systems modeling, Software development, Calibration, Analog electronics, Space telescopes
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.
We describe the design, characterization and performance of the IR Camera for Adaptive Optics at Lick (IRCAL). IRCAL is a 1-2.5 micron camera optimized for use with the LLNL Lick adaptive optics system on the Shane 3 m telescope. Using diamond-turned gold-coated optics, the camera provides high efficiency diffraction limited imaging throughout the near- IR. IRCAL incorporates optimizations for obtaining high dynamic range images afforded by adaptive optics, coronagraphic masks, and a cross-dispersed silicon grism for high resolution spectroscopy.
This paper describes an electronic logsheet designed to be easily connected to both existing and new instruments for the Lick and Keck Observatories. The primary motivation for such a log is to automate the recording of basic observing parameters in a form that preserves the best characteristics of paper logs: columns that can be readily annotated with text or sketches, and user choice of what data form the log. To these capabilities, Electrolog adds simultaneous viewing/editing by local and/or remote observers, who can share annotations and emendations, if desired. The log can be written out in plain text, in 'pretty-printed' PostScript, as a FITS ASCII table extension, or as a native- format dump. Either the FITS file or the dump format can be read back in by another instance of the logsheet. It is simple to splice the logsheet into existing data-taking programs. It accepts data in a variety of formats, including raw FITS image headers. As a useful side-effect, a dozen- line Tcl script can generate 'retrospective' logs form a set of FITS image files.
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