Commissioned in November 2022 at W. M. Keck Observatory (WMKO), the Keck Planet Finder (KPF) instrument is a fiber-fed high-resolution spectrometer, developed in partnership with California Institute of Technology, University of California Berkeley Space Science Laboratory, and University of California at Santa Cruz. At the heart of object acquisition and tracking is KPF’s guiding system, which uses 100 Hz tip/tilt corrections to maintain the target on the fiber aperture, and coarse telescope corrections to keep the target within the effective range of the tip/tilt mechanism. This paper covers the design of the guider software at the heart of these corrections, emphasizing simplicity for the initial approach, deliberately avoiding potentially unnecessary optimization, while leveraging existing standards and practices at WMKO. The software is implemented in Python with one key component written in C. The paper covers the gradual process of optimization, addressing critical performance bottlenecks in targeted fashion without rewriting the bulk of the code; the bottlenecks include image acquisition, image transmission, command transmission, and image processing. This paper concludes with an analysis of the tip/tilt performance on-sky.
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 to produce transformative discoveries that keep the U.S. observing community on the frontiers of astronomical research. Upgraded capabilities and new instrumentation are provided though collaborative partnerships primarily with the Caltech and University of California instrument development teams and through additional collaborations with the University of Notre Dame, the University of Hawaii, Swinburne University of Technology, industry, and other organizations. This paper summarizes the status and performance of observatory infrastructure projects, technology upgrades, and new additions to the suite of observatory instrumentation. We also provide a status of instrumentation projects in early and advanced stages of development that will achieve the goals and objectives summarized in the 2023 Keck Observatory strategic plan. Developed in collaboration with the WMKO science community, the Keck strategic plan sets our sites on 2035 and meets goals identified in the Astro2020 Decadal Survey.
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, echelle spectrometer that specializes in the discovery and characterization of exoplanets using Doppler spectroscopy. In designing KPF, the guiding principles were high throughput to promote survey speed and access to faint targets, and high stability to keep uncalibrated systematic Doppler measurement errors below 30 cm s−1. KPF achieves optical illumination stability with a tip-tilt injection system, octagonal cross-section optical fibers, a double scrambler, and active fiber agitation. The optical bench and optics with integral mounts are made of Zerodur to provide thermo-mechanical stability. The spectrometer includes a slicer to reformat the optical input, green and red channels (445–600 nm and 600–870 nm), and achieves a resolving power of ∼97,000. Additional subsystems include a separate, medium-resolution UV spectrometer (383–402 nm) to record the Ca II H & K lines, an exposure meter for real-time flux monitoring, a solar feed for sunlight injection, and a calibration system with a laser frequency comb and etalon for wavelength calibration. KPF was installed and commissioned at the W. M. Keck Observatory in late 2022 and early 2023 and is now in regular use for scientific observations. This paper presents an overview of the as-built KPF instrument and its subsystems, design considerations, and initial on-sky performance.
For 25 years, W. M. Keck Observatory has relied on observers to do their own planning for their observing nights. This would usually result in a starlist and a notion of what would be best to observe next based on the priority to the science they were conducting. Under the Data Services Initiative, this will become a required part of observing. The Database-Driven Observing Infrastructure aims to supplement the creation of science-ready data by carrying observation metadata throughout the observing process. The result is a file with all the data about the observation ready to be processed by the pipelines. In order to facilitate this, tools are being developed to help create better observing plans. One of the big complexities is that W. M. Keck Observatory currently supports ten active instruments with more on the horizon and no clear plan of retiring old instruments. With that in mind, the Database-Driven Observing Infrastructure system has been developed to be modular and instrument agnostic so that differences are abstracted from the system and handled only at the entrance and exit points of an observation. The benefit to this is that new instruments are easy to implement and old instruments are easy to update.
As part of the Keck Planet Finder (KPF) project, a Fiber Injection Unit (FIU) was implemented and will be deployed on the Keck Ⅰ telescope, with the aim of providing dispersion compensated and tip/tilt corrected light to the KPF instrument and accompanying H&K spectrometer. The goal of KPF is to characterize exoplanets via the radial velocity technique, with a single measurement precision of 30cm/s or better. To accomplish this, the FIU must provide a stable F-number and chief ray angle to the Science and Calcium H&K fibers. Our design approach was use a planar optical layout with atmospheric dispersion compensation for both the Science and Calcium H&K arms. A SWIR guider camera and piezo tip/tilt mirror are used to keep the target centered on the fibers.
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.
To maintain and expand its scientific productivity and impact, the W. M. Keck Observatory is undertaking a new strategic project to redefine how the Observatory approaches the creation of science products: the Data Services Initiative (DSI). The philosophy of DSI is grounded in the principle that the future of astronomy requires that data must be usable, useful, and quick. Reaching these data goals requires significant changes to key elements of the observing process: observation preparation, observation execution and calibration association, data reduction, and data archiving.
In this presentation, we will introduce DSI and its components, and describe the science gains that are enabled by it.
With the release in August 2021 of the Intergovernmental Panel on Climate Change sixth assessment report1 , the crisis of climate change is irrefutable and the critical need for action to address it has gained broad support throughout the global community. As stewards of the W. M. Keck Observatory on Maunakea and considering our place in our island community and the global community, it is important that we lay the groundwork for examining sustainability measures, attainable goals and viable paths to meet those goals. This paper presents a methodology for viewing and measuring one aspect of the sustainability challenge which can inform the development of a sustainability strategy for WMKO. One of the most notable challenges facing the global community is realizing a significant reduction in greenhouse gases which are contributing to accelerating climate change and increasing probability of extreme weather events. We present an understanding of the key contributors to WMKO’s carbon footprint, initial estimates of what that footprint was for 2019 and some opportunities and next steps towards developing and executing on a plan to reduce it over the coming decade.
The remote observing system at W. M. Keck Observatory has been in place for more than 20 years, but prior to 2020, it had focused on providing observing access only to observers physically located at a prescribed set of formal sites, typically dedicated rooms located at member universities in the Keck partnership. The Novel Coronavirus pandemic of 2020 forced a rapid and drastic change in the philosophy and design of the Keck remote observing system. These changes were made in two phases. The first phase could be characterized as triage or emergency response, while the second phase focused on longer term issues such as security, staff support, and maintainability of the system.
Consumer-level digital single-lens reflex (DSLR) cameras are typically not used in professional astronomy because of the systematic errors present in the data as a result of the strong intra- and interpixel variations associated with each of the three different colors (RGB) of the Bayer color filter array. Nevertheless, because the cost of DSLRs compared with traditional astronomical CCDs is so much lower, they represent a potentially underexplored area of scientific quality astronomical imaging, especially in the area of wide-field transient surveys. We demonstrate an algorithm that can achieve ≈ 1 % level photometry in each of the RGB color channels from a stellar source and discuss the application of this algorithm to a ground-based transiting exoplanet survey. The algorithm primarily takes advantage of the large number of stellar sources available for statistical averaging within a single image, using a “lucky point-spread function” approach to identify sources in the image that exhibit systematic errors consistent with a chosen target from the same image. The selection of the appropriate“lucky” reference stars is accomplished through a comparison of the stellar image morphology as it appears on the Bayer array and the reference stars. These references are linearly combined to form a synthetic comparison star that can be used for differential photometry with the target. One key to the algorithm is that all data are retained at the individual pixel-level until the final differential comparison, which helps to alleviate systematic effects that might otherwise cancel each other out during the flux-summing process. We demonstrate the algorithm on HD 339461, a mV = 8.93 G0-type star on which we achieve single-percent level photometry that approaches the fundamental noise floor possible from a single camera.
PANOPTES (Panoptic Astronomical Networked Observatories for a Public Transiting Exoplanets Survey) is a citizen science project that aims to build a collaborative, worldwide network of robots that will survey the night sky for nearby transiting exoplanets. The PANOPTES units are designed to be low-cost, easy to build with a clear set of instructions, and constructed with readily available off-the-shelf hardware. As part of collaborative efforts, we have established an online forum for the PANOPTES community. The forum serves as a platform for everyone involved in PANOPTES to discuss with each other, to help troubleshoot during the build and deployment of a unit, and to provide feedback in improving the design. PANOPTES units have been built by school students, graduate students, astronomy enthusiasts, and citizen scientists from different countries. There are currently 18 units in various stages of deployment across the world, with at least seven more units being planned for construction. The degree of success of the project relies directly on the number of units spread over the world, as light curves from different units in the network will be combined to improve sensitivity and time coverage. In this paper, we provide an overview of the project, its scientific goals, community reach, current status, challenges, and future plans.
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.
PANOPTES is a citizen-science based project to discover exoplanets with consumer cameras. It is open source and aims to be highly efficient at collecting photometric data by running a wide field survey using DSLR cameras and standard lenses. In the two years since the demonstration of the baseline design at SPIE 2016 the project has moved forward in getting the hardware design ready for citizen scientists and data analysis, benefiting from an influx of both professional and amateur support. At the same time the project has experienced a number of challenges related to the nature of a grassroots project with no specific institutional home. Here we present a status update to the project with a focus on the issues associated with creating, and maintaining, a successful “pro-am” astronomy project.
This talk will specifically focus on a couple of keys concepts related to the operation of PANOPTES as a distributed observatory built by a collection of professional and amateur astronomers. These concepts can largely be broken down as: software; hardware; and organizational. However, a central theme of the talk will also be the fact that PANOPTES operates without a centralized institution, which means that decisions related to software and hardware are necessarily tied into the organizational decisions. Likewise, since the project has no official operating budget but operates largely off the budgets of each individual team (in addition to a NASA/JPL grant, the attainment of which will also be discussed), the hardware decisions and the evolving landscape of commercial over-the-counter (COTC) hardware play a significant role in the operation and maintenance of the project as a whole, which in turn affects how the software is developed.
Through all of these areas PANOPTES has experienced successes and failures as well as simple deviations from original plans. As a project we have benefited enormously from the donation of time and storage on the Google Cloud Platform (GCP), allowing us to explore technologies and solutions that would otherwise be unfeasible, but as an unofficial project we have been unable to secure a permanent formal agreement with GCP, creating challenges related to the long-term viability of those software solutions.
Being a unique project that aims to be as scientifically productive as it is successful as an outreach tool, it is hoped that the talk will provide some valuable learned lessons for any future projects that hope to utilize the unique professional-amateur dynamic that exists within the field of astronomy and open-source software.
In 2014 and 2015 the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) instrument at the Subaru Telescope on Maunakea is underwent a significant modernization and upgrade project. We upgraded the two Hawaii2 detectors to Hawaii2-RG models, modernized the cryogenic temperature control system, and rewrote much of the instrument control software. The detector upgrade replaced the Hawaii2 detectors which use the Tohoku University Focal Plane Array Controller (TUFPAC) electronics with Hawaii2-RG detectors using SIDECAR ASIC (a fully integrated FPA controller system-on-a-chip) and a SAM interface card. We achieved an improvement in read noise by a factor of about 2 with this detector and electronics upgrade. The cryogenic temperature control upgrade focused on modernizing the components and making the procedures for warm up and cool down of the instrument safer. We have moved PID control loops out of the instrument control software and into Lakeshore model 336 cryogenic temperature controllers and have added interlocks on the warming systems to prevent overheating of the instrument. Much of the instrument control software has also been re-written. This was necessitated by the different interface to the detector electronics (ASIC and SAM vs. TUFPAC) and by the desire to modernize the interface to the telescope control software which has been updated to Subaru's "Gen2" system since the time of MOIRCS construction and first light. The new software is also designed to increase reliability of operation of the instrument, decrease overheads, and be easier for night time operators and support astronomers to use.
During the past year, the Multi-Object InfraRed Camera and Spectrograph at Subaru has undergone an upgrade of its science detectors, the housekeeping electronics and the instrument control software. This overhaul aims at increasing MOIRCS' sensitivity, observing efficiency and stability. Here we present the installation and the alignment procedure of the two Hawaii 2RG detectors and the design of a cryogenic focus mechanism. The new detectors show significantly lower read noise, increased quantum efficiency, and lower the readout time.
Project PANOPTES (http://www.projectpanoptes.org) is aimed at establishing a collaboration between professional astronomers, citizen scientists and schools to discover a large number of exoplanets with the transit technique. We have developed digital camera based imaging units to cover large parts of the sky and look for exoplanet transits. Each unit costs approximately $5000 USD and runs automatically every night. By using low-cost, commercial digital single-lens reflex (DSLR) cameras, we have developed a uniquely cost-efficient system for wide field astronomical imaging, offering approximately two orders of magnitude better etendue per unit of cost than professional wide-field surveys. Both science and outreach, our vision is to have thousands of these units built by schools and citizen scientists gathering data, making this project the most productive exoplanet discovery machine in the world.
The Panoptic Astronomical Networked OPtical observatory for Transiting Exoplanets Survey (PANOPTES, www.projectpanoptes.org) project is aimed at identifying transiting exoplanets using a wide network of low-cost imaging units. Each unit consists of two commercial digital single lens reflex (DSLR) cameras equipped with 85mm F1.4 lenses, mounted on a small equatorial mount. At a few $1000s per unit, the system offers a uniquely advantageous survey eficiency for the cost, and can easily be assembled by amateur astronomers or students. Three generations of prototype units have so far been tested, and the baseline unit design, which optimizes robustness, simplicity and cost, is now ready to be duplicated. We describe the hardware and software for the PANOPTES project, focusing on key challenging aspects of the project. We show that obtaining high precision photometric measurements with commercial DSLR color cameras is possible, using a PSF-matching algorithm we developed for this project. On-sky tests show that percent-level photometric precision is achieved in 1 min with a single camera. We also discuss hardware choices aimed at optimizing system robustness while maintaining adequate cost. PANOPTES is both an outreach project and a scientifically compelling survey for transiting exoplanets. In its current phase, experienced PANOPTES members are deploying a limited number of units, acquiring the experience necessary to run the network. A much wider community will then be able to participate to the project, with schools and citizen scientists integrating their units in the network.
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