The first scientific observations with adaptive optics (AO) at W. M. Keck Observatory (WMKO) began in 1999. Through 2023, over 1200 refereed science papers have been published using data from the WMKO AO systems. The scientific competitiveness of AO at WMKO has been maintained through a continuous series of AO and instrument upgrades and additions. This tradition continues with AO being a centerpiece of WMKO’s scientific strategic plan for 2035. We will provide an overview of the current and planned AO projects from the context of this strategic plan. The current projects include implementation of new real-time controllers, the KAPA laser tomography system and the HAKA high-order deformable mirror system, the development of multiple advanced wavefront sensing and control techniques, the ORCAS space-based guide star project, and three new AO science instruments. We will also summarize steps toward the future strategic directions which are centered on ground-layer, visible and high-contrast AO.
The ORCAS Keck Instrument Demonstrator (ORKID) is a visible-light diffraction-limited camera that was installed behind the WMKO Keck II AO system in the fall of 2022. Its primary purpose is to act as a pathfinder instrument for adaptive optics-fed visible-light imaging at Keck, with consideration for upcoming AO upgrades and future possibilities. ORKID is diffraction-limited down to 650nm and can operate with millisecond frame rates, enabling frame selection and frame registration in post-processing. Here we provide an overview of the commissioning of the instrument and describe its on-sky performance. Using Keck’s current AO deformable mirror, and its Shack-Hartmann and pyramid wavefront sensors, we are able to achieve images with point-spread function cores of 15-17 milliarcseconds FWHM. We report here on early observations obtained within the first year of operations and we provide a gallery of scientific objects of interest with ORKID, as a preview for future capabilities.
The Orbiting Configurable Artificial Star (ORCAS) mission in collaboration with the W. M. Keck Observatory (WMKO) is poised to deliver near diffraction limited observations in visible light. The ability to conduct such observations will enable significant scientific discoveries in fields related to Active Galactic Nuclei (AGN), Dark Energy, Flux Calibration, the High Redshift Universe, Exoplanets, and the Solar System. The ORCAS team has successfully completed three primary mission development goals to enable such observations. The performance demonstration with the ORCAS Keck Instrument Demonstrator (ORKID) captured arguably the highest resolution image at visible wavelengths from a large (10 meter) segmented telescope on the ground to date. High resolution AO imaging of the galaxy UGC 4729 in Natural Guide Star (NGS) mode was performed by locking onto a foreground asteroid passing nearby, which simulated an observation with a moving guide star validating post processing capabilities and demonstrating how regions unreachable by NGS and LGS could be explored. Additionally, the ORCAS team has successfully locked onto a laser source onboard the Laser Communications Relay Demonstration (LCRD) and closed the adaptive optics loop to perform near diffraction limited imaging at 1550 nm with the Keck 10 meter, the first demonstration of such capability with a large segmented telescope. All of these results validate the feasibility of the ORCAS mission. Following these accomplishments, ORCAS will be strongly positioned to propose a full-scale mission to upcoming opportunities.
We present a recent evaluation and updates applied to the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck I telescope. Over the course of significantly long integrations, when MOSFIRE sits on one mask for >4 hours, a slight drift in mask stars has been measured. While this does not affect all science-cases done with MOSFIRE, the drift can smear out signal for observers whose science objective depends upon lengthy integrations. This effect was determined to be the possible result of three factors: the internal flexure compensation system (FCS), the guider camera flexure system, and/or the differential atmospheric refraction (DAR) corrections. In this work, we will summarize the three systems and walk through the current testing done to narrow down the possible culprit of this drift and highlight future testing to be done.
The new Keck Observatory Telescope Control System is now deployed for regular operations on Keck 2 and the deployment on both telescopes, Keck 1 and Keck 2, is expected to be completed by the time this paper is published. Two new instruments, KCWI and NIRES, were commissioned with the new control system on Keck 2. The upgrade project was a major undertaking replacing the original software architecture and modules, as well as many obsolete hardware components. During the long testing phase, we discovered deficiencies, which we corrected with modifications of the original design. This paper gives a summary of the achieved performance, the issues involving deploying a new system while remaining in full operation, and lessons learned in design and implementation of such a large system.
Launched in 2009, Keck Observatory’s Telescope Control System Upgrade (TCSU) project set out to improve Keck’s telescope pointing, tracking, and offsetting performance as well as increase maintainability and reliability. The project went online full time on the Keck 2 telescope in October 2017 and on the Keck 1 telescope in March 2018 after a notable delay due to a re-design of the azimuth and elevation encoder mounting systems. This paper discusses the details and challenges of implementing this large and complicated system while never requiring a shutdown of either telescope. The TCSU project replaced all of the major elements of the telescope controls, rotator and secondary mirror controls, and safety system. National Instrument’s reconfigurable I/O technology (i.e. NI RIO), with their embedded field programmable gate arrays (FPGAs), are used as the core of the telescope’s digital velocity control loop, structural filter, and tachometer filter. They were also used to create a monitoring and safety system for the rotator velocity controller as well as reading the newly installed tilt meters used to greatly improve pointing performance. Delta Tau’s family of “Brick” programmable multi-axis controllers, i.e. PMAC or BRICK, are used to control the rotator and secondary mirror. They enable better tuning and faster slew speeds for these subsystems. An Allen Bradley’s ControlLogix® controller and the family of FLEX™ Input/Output (IO) modules were used to create a distributed safety system able to handle a wide variety of signal types. This technology refresh based on commercial off the shelf equipment replaced much of our obsolete and custom equipment. A significant part of the project was the installation of new telescope azimuth and elevation position encoders based on Heidenhain’s 40 micron grading tape scales. Interpolated to a 10 nanometer resolution, the new encoders provide true 4 mas resolution in azimuth and 1 mas resolution in elevation. This is a big improvement to Keck’s position sensing when compared to the old rotary incremental encoders. The installation required a significant amount of mechanical infrastructure to house them. Additionally, two tilt meters were installed to sense the telescope’s varying vertical angle as a function of azimuth, mainly due to the azimuth bearing’s axial runout. The encoders and tilt meters are the primary reason for achieving the greatly improved pointing and tracking performance [1]. Finally, a switching solution using solid state relays and dual network switches was installed to provide seamless and rapid switching between the old and new control systems during commissioning. Although this component is a simple design and does not boast of any new technology, it is one of the key components that enabled the successful testing of the new equipment while keeping the old system operational as a backup for night time observing as well as for baseline performance comparisons. It allowed us to switch a variety of signal types and was very cost effective when compared to available products.
Since the start of operations in 1993, the twin 10 meter W. M. Keck Observatory 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 and UC instrument development teams. The observatory adapts and responds to the observers’ evolving needs as defined in the observatory’s strategic plan, periodically refreshed in collaboration with the science community. This paper summarizes the performance of recently commissioned infrastructure projects, technology upgrades, and new additions to the suite of instrumentation at the observatory. We will also provide a status of projects currently in the design or development phase, and since we need to keep our eye on the future, we mention projects in exploratory phases that originate from our strategic plan. Recently commissioned projects include telescope control system upgrades, OSIRIS spectrometer and imager upgrades, and deployments of the Keck Cosmic Web Imager (KCWI), the Near-Infrared Echellette Spectrometer (NIRES), and the Keck I Deployable Tertiary Mirror (KIDM3). Under development are upgrades to the NIRSPEC instrument and adaptive optics (AO) system. Major instrumentation in design phases include the Keck Cosmic Reionization Mapper and the Keck Planet Finder. Future instrumentation studies and proposals underway include a Ground Layer Adaptive Optics system, NIRC2 upgrades, the energy sensitive instrument KRAKENS, an integral field spectrograph LIGER, and a laser tomography AO upgrade. Last, we briefly discuss recovering MOSFIRE and its return to science operations.
Pointing and tracking performance is one of the key metrics that characterize a telescope's overall efficiency. The pointing performance of the Keck telescopes, which use rotary friction encoders to provide position feedback to the control system, has been surpassed by newer large telescopes with more precise encoder systems. While poor tracking can be compensated with guiding, poor blind pointing performance can lead to loss of observing time. In this paper we present a history of the efforts to reduce the impact of poor pointing, as well as the improvements achieved after the installation of new tape encoders. We will discuss the calibration and testing methods and the tools for monitoring and maintaining the desired pointing performance. A comparative analysis of the pointing performance before and after the telescope control system upgrade will also be presented.
The Maunakea Laser Traffic Control System (LTCS) has been in use since 2002 providing a mechanism to prevent the laser guide star or Rayleigh scatter from a laser propagated from one telescope from interfering with science observations at any of the other telescopes that share the mountain. LTCS has also been adopted at several other astronomical sites around the world to address that same need. In 2014 the stakeholders on Maunakea began the process of improving LTCS capability to support common observing techniques with enhanced First On Target (FoT) equity. The planned improvements include support for non-sidereal observing, laser checkout at zenith, dynamic field of view size, dithering, collision calculations even when a facility is not laser impacted, multiple alert severity levels, and software refactoring. The design of these improvements was completed in early 2015, and implementation is expected to be completed in 2016. This paper describes the Maunakea LTCS collaboration and the design of these planned improvements.
One of the primary scientific limitations of adaptive optics (AO) has been the incomplete knowledge of the point spread function (PSF), which has made it difficult to use AO for accurate photometry and astrometry in both crowded and sparse fields, for extracting intrinsic morphologies and spatially resolved kinematics, and for detecting faint sources in the presence of brighter sources. To address this limitation, we initiated a program to determine and demonstrate PSF reconstruction for science observations obtained with Keck AO. This paper aims to give a broad view of the progress achieved in implementing a PSF reconstruction capability for Keck AO science observations.
This paper describes the implementation of the algorithms, and the design and development of the prototype operational tools for automated PSF reconstruction. On-sky performance is discussed by comparing the reconstructed PSFs to the measured PSF’s on the NIRC2 science camera. The importance of knowing the control loop performance, accurate mapping of the telescope pupil to the deformable mirror and the science instrument pupil, and the telescope segment piston error are highlighted. We close by discussing lessons learned and near-term future plans.
Until a few years ago, the W. M. Keck Observatory (WMKO) did not have a systematic program of instrument maintenance at a level appropriate for a world-leading observatory. We describe the creation of such a program within the context of WMKO’s lean operations model which posed challenges but also guided the design of the system and resulted in some unique and notable capabilities. These capabilities and the flexibility of the system have led to its adoption across the Observatory for virtually all PM’s. The success of the Observatory in implementing the program and its impact on instrument reliability are presented. Lessons learned are reviewed and strategic implications discussed.
The W. M. Keck Observatory has completed the development and initial deployment of MAGIQ, the Multi-function
Acquisition, Guiding and Image Quality monitoring system. MAGIQ is an integrated system for acquisition, guiding and
image quality measurement for the Keck telescopes. This system replaces the acquisition and guiding hardware and
software for existing instruments at the Observatory and is now the standard for visible wavelength band acquisition
cameras for future instrumentation. Innovative features are provided in the MAGIQ software for use by observers and
telescope operators including advanced capabilities for acquisition and image quality monitoring. In this paper we report
on the design and implementation of the MAGIQ software components, including the process for developing
requirements, the implementation choices and strategies, the software features and user interfaces, and the challenges of
test and deployment in a working observatory.
We describe the system to monitor and analyze the duty cycle of observing nights at the W. M. Keck Observatory. The
system is almost completely automated, and relies predominantly on existing data. Lists of discrete "events" during the
night are compiled (e.g. the start of a science exposure), and the sequence of events is interpreted as an "activity" (e.g.
collecting science photons). The metrics system has proven extremely valuable, allowing scientists and engineers to
identify the largest causes of inefficiency, and to quantify their impacts. This has led directly to prioritization decisions
in upgrades and repairs at the Observatory.
The W. M. Keck Observatory has completed the development and initial deployment of MAGIQ, the Multi-function
Acquisition, Guiding and Image Quality monitoring system. MAGIQ is an integrated system for acquisition, guiding and
image quality measurement for the Keck telescopes. This system replaces the acquisition and guiding hardware and
software for existing instruments at the Observatory and is now the standard for visible wavelength band acquisition
cameras for future instrumentation. In this paper we report on the final design and implementation of this new system,
which includes three major components: a visible wavelength band acquisition camera, image quality measurement
capability, and software for acquisition, guiding and image quality monitoring. The overall performance is described, as
well as the details of our approach to integrating low order wavefront sensing capability in order to provide closed loop
control of telescope focus.
The Laser Guide Star Adaptive Optics (LGS AO) at the W.M. Keck Observatory is the first system of its kind being used to conduct routine science on a ten-meter telescope. In 2005, more than fifty nights of LGSAO science and engineering were carried out using the NIRC2 and OSIRIS science instruments. In this paper, we report on the typical performance and operations of its LGS AO-specific sub-systems (laser, tip-tilt sensor, low-bandwidth wavefront sensor) as well as the overall scientific performance and observing efficiency. We conclude the paper by describing our main performance limitations and present possible developments to overcome them.
The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angular resolution imaging and spectroscopy in the near infrared. In this paper, we present the result of a unique project to map the entire surface of Io in the thermal infrared (Lp band centered at 3.8 μm). This project was undertaken by a team from the W. M. Keck Observatory and UC Berkeley to illustrate the power of this instrumentation. The 75-milliarcsec-resolution images, corresponding to ~200 km of linear spatial resolution on Io, have been combined to build a thermal infrared map of the entire satellite. We have identified 26 hot spots including one that was undetected by the Galileo mission. A movie and a Java applet featuring a volcanically active rotating satellite were created.
Mira is the name of a program that measures and improves the image quality of the Keck Telescopes by correcting misalignments of the secondary mirror and adjusting the segments of the primary mirror. It is used regularly to achieve optimal focus calibration. Mira is completely written in Java. During the design phase, several software design patterns were followed resulting in short implementation times and a robust product. In this paper, we first discuss the operation of Mira, and then we present four examples of design patterns, describing the problem, the solution and the implementation.
Keywords, a concept that uses named parameters to access information from devices and instruments, originated in the early 1990s and is the foundation of the Keck Task Library, KTL. KTL uses different underlying communication schemes to provide a consistent API to a diversity of client applications. Increasing instrument complexity, the need to integrate multiple subsystems into a unified whole, and the demand for greater flexibility and productivity in the software development process, has prompted us to review the concept of keywords and its implementation. In this paper, we discuss the application of modern software methodology and communication protocols to enhance the Keck Task Library.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.