We present Maratus—a proposed 12U cubesat far ultraviolet narrow-band imager, centered on 1350Å to map the circumgalactic medium (CGM). We primarily target O vi emission, likely the brightest tracer of the 105 −106 K gas surrounding galaxies, at z ∼ 0.3. Combining flight-proven hardware with recent technological improvements, we tackle one of the most interesting questions bridging large scale structure and galaxy evolution in our current moment — “How does gas flow into and out of galaxies?” Answering this question is crucial for understanding the regulation of star formation, and the flow of matter, energy, and metals travelling between galaxies and the intergalactic medium. Maratus is a proof of principle instrument that will pave the way for large-scale mapping of the intergalactic medium. Mapping the CGM is identified as a key discovery area in the recent astrophysics decadal report. By using COS-Halos galaxies for our targeted survey, we present the first opportunity to characterize a key metal tracer of the CGM in both emission and absorption.
Ground-based telescopes require useful and productive instruments to stay relevant in astronomy. The Kitt Peak Ohio State Multi Object Spectrograph (KOSMOS), originally on the Kitt Peak National Observatory (KPNO) 4-meter Mayall Telescope, is a long-slit and multi-object, low-resolution spectrograph. KOSMOS was acquired by the Astrophysical Research Consortium (ARC) for the Apache Point Observatory (APO) ARC 3.5m telescope, implemented redesigns to the instrument, and renamed KOSMOS II. The instrument was integrated into the ARC 3.5m's operational environment by adding a Nasmyth port adapter, a cart with truss for mechanical support, and telescope user interface (TUI) software. Upgrades include slit-viewing guiding, internal calibration lamps, heat exhaust, and a new cryostat. Since 2021, KOSMOS II has proven capable of the high-throughput, low-resolution spectroscopy required by the ARC 3.5m user community. This paper describes the design updates and revisions made to the instrument along with measurements of its performance.
The Sloan Digital Sky Survey V (SDSS-V) is an all-sky, multi-epoch spectroscopic survey designed to decode the stellar evolution of the Milky Way, reveal the inner workings of stars, study the interstellar medium in the Local Volume of galaxies, and track the growth of supermassive black holes across the Universe. SDSS-V presents significant innovations in hardware and instrumentation, with the introduction of a new Focal Plane System instrument that enables multi-object spectroscopy using an array of 500 robotic fibre positioners, and the development of a new robotic observatory for the Local Volume Mapper program. These advances in instrumentation and operations necessitate a similarly evolved computing and software architecture to ensure survey efficiency and to take advantage of the improvements in software engineering and development. In this paper we present the cyberinfrastructure of the SDSS project with focus on the changes introduced since the previous iteration of the project, the adoption of new technologies, and the lessons learned in this process.
The Sloan Digital Sky Survey V (SDSS-V) is an all-sky spectroscopic survey of <6 million objects, designed to decode the history of the Milky Way, reveal the inner workings of stars, investigate the origin of solar systems, and track the growth of supermassive black holes across the Universe. The robotic Focal Plane System (FPS) carries 500 robotic fiber positioners, 60 stationary Fiber-Illuminated Fiducials (FIFs), and 6 Guide, Focus, and Acquisition cameras (GFAs). The GFAs find and use guide stars to compute target positions for the robots. The FIFs provide a reference basis against which precise measurements of the robot positions can be made using the Fiber Viewing Camera (FVC). Once imaged by the FVC, closed loop control allows the robots to reach their commanded positions to within 12 microns of precision. This paper discusses the metrology process for the FIFs and GFAs, thus allowing for accurate robot moves and reliable FVC measurements.
The Sloan Digital Sky Survey V (SDSS-V) is an all-sky spectroscopic survey of <6 million objects, designed to decode the history of the Milky Way, reveal the inner working of the stars, investigate the origin of solar systems, and track the growth of supermassive black holes across the Universe. Here we describe the mathematical frame work behind the SDSS-V robotic Focal Plane System (FPS), specifically the coordinate systems and transforms used to propagate locations of targets from astronomical catalogs to coordinates on a robotically positioned fiber or guide camera. This framework provides the backbone for the design and operations of SDSS-V’s MOS surveys. All coordinate systems and transformations between them are provided in SDSS-V’s coordio software package.
We describe the on-sky performance of the robotic Focal Plane System (FPS) units that replace the fiber plug-plate systems at the Sloan and duPont telescopes for the SDSS-V survey. The first FPS was arrived at Apache Point in December 2021, and the second unit will be delivered to Las Campanas in spring 2022. Each FPS carries 500 zonal fiber positioners carrying three fibers: two science fibers for the BOSS and APOGEE spectrographs and a back-illuminated metrology fiber. The FPS enables the SDSS-V Milky Way and Black Hole Mapper surveys that will begin survey operations in 2022.
The Fifth iteration of the Sloan Digital Sky Survey entered the instrument commissioning phase for its robotic fibre positioner (FPS) in December 2021 and will move into full science operations shortly after. The guiding system for the FPS consists of six CCD cameras located in the periphery of the field of view of the instrument; these cameras are used for field acquisition, guiding, and focus corrections. In this presentation I will describe the instrument setup, design choices, focal plane modelling, and the software tools used for acquisition and guiding. Acquisition is performed using an offline version of the astrometry.net software (Lang et al. 2010) while guiding uses a preselected list of source stars from the Gaia catalogue. I will discuss the performance of the system, possible improvements, and lessons learned from the design and development process.
The Sloan Digital Sky Survey V (SDSS-V) is an all-sky spectroscopic survey of more than 6 million objects, designed to decode the history of the Milky Way, reveal the inner workings of stars, investigate the origin of solar systems, and track the growth of supermassive black holes across the Universe. SDSS-V presents significant innovations in both hardware and software, chiefly due to the introduction of a robotic Focal Plane System (FPS) that replaces plug-plate operations. This new mode of operations introduces new challenges with respect to target scheduling, fibre robot positioner reconfiguration optimisation, telescope guiding, observer interfaces, and observatory operations. During normal operations SDSS-V will observe a new field every 15 minutes. For each field requiring a new telescope pointing the FPS will reconfigure 500 robotic fibre positioners with feedback from an external Field Viewing Camera (FVC) in less than two minutes. Six CCD cameras mounted on the FPS will be used to automatically acquire the field and maintain the necessary guiding accuracy. These strict requirements highlight the need for streamlined operations software and procedures to minimise the time spent during FPS reconfigurations. We describe the overall design and implementation of the SDSS-V survey operations, with special emphasis on software development, conventions, and observing procedures. While specific to SDSS-V, the solutions we describe can be readily applied to other astronomical surveys and are of special interest given the rapid increase in projects employing robotic fibre positioners.
This paper will focus on the testing, validation and performance of the ongoing SDSS-V fiber positioners production. The tested critical parameters include positioning accuracy calibration and validation, fiber misalignment control as well as lifetime test and thermal reliability check over the large temperature scale encountered in the telescopes. The presented results give a good overview on the general design performance and on the general reliability the complete robotic positioning system will achieve.
The Sloan Digital Sky Survey V (SDSS-V) is an all-sky spectroscopic survey of <6 million objects, designed to decode the history of the Milky Way, reveal the inner workings of stars, investigate the origin of solar systems, and track the growth of supermassive black holes across the Universe. This paper describes the design and construction of two robotic Focal Plane System (FPS) units that will replace the traditional SDSS fiber plug-plate systems at the Sloan and du Pont telescopes for SDSS-V. Each FPS deploys 500 zonal fiber positioners that allow us to reconfigure the fibers onto a new target field within 2-3 minutes of acquisition. Each positioner carries three fibers: two science fibers that feed the BOSS and APOGEE spectrographs and a third back-illuminated metrology fiber is used in conjunction with a telescopemounted Fiber Viewing Camera (FVC) to measure the absolute positions of the fiber heads. The 300 APOGEE fibers are distributed among the 500 positioners to maximize common field coverage. A set of fiber-illuminated fiducials distributed in and around the positioner array establish a fixed reference frame for the FVC system. Finally, six CCD cameras mounted around the periphery of the focal plane provide acquisition, guiding, and focus monitoring functions. The FPS is a key enabling technology of the SDSS-V Milky Way and Black Hole Mapper surveys.
Joseph Huehnerhoff, William Ketzeback, Alaina Bradley, Jack Dembicky, Caitlin Doughty, Suzanne Hawley, Courtney Johnson, Mark Klaene, Ed Leon, Russet McMillan, Russell Owen, Conor Sayres, Tyler Sheen, Alysha Shugart
The Astrophysical Research Consortium Telescope Imaging Camera, ARCTIC, is a new optical imaging camera now in use at the Astrophysical Research Consortium (ARC) 3.5m telescope at Apache Point Observatory (APO). As a facility instrument, the design criteria broadly encompassed many current and future science opportunities, and the components were built for quick repair or replacement, to minimize down-time. Examples include a quick change shutter, filter drive components accessible from the exterior and redundant amplifiers on the detector. The detector is a Semiconductor Technology Associates (STA) device with several key properties (e.g. high quantum efficiency, low read-noise, quick readout, minimal fringing, operational bandpass 350-950nm). Focal reducing optics (f/10.3 to f/8.0) were built to control aberrations over a 7.8'x7.8' field, with a plate scale of 0.11" per 0.15 micron pixel. The instrument body and dewar were designed to be simple and robust with only two components to the structure forward of the dewar, which in turn has minimal feedthroughs and permeation areas and holds a vacuum <10-8 Torr. A custom shutter was also designed, using pneumatics as the driving force. This device provides exceptional performance and reduces heat near the optical path. Measured performance is repeatable at the 2ms level and offers field uniformity to the same level of precision. The ARCTIC facility imager will provide excellent science capability with robust operation and minimal maintenance for the next decade or more at APO.
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