Space-qualified, abuttable packaging for LBNL p-channel CCDs, part II

Besuner, Robert; Baltay, C.; Diehl, H. T.; Emmet, W.; Harris, S.; Jelinsky, Patrick; Krider, J.; Rabinowitz, D.; Roe, Natalie A.

doi:10.1117/12.856469

Cited by 4 publications

(4 citation statements)

References 11 publications

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“…1. First, DESI underwent commissioning (e.g., Besuner et al 2020;Meisner et al 2020;Perruchot et al 2020;Poppett et al 2020;Shourt et al 2020) Collaboration, 2023, in preparation). The major objectives of this phase were to validate the end-to-end DESI systems, to provide observations to refine the purity and completeness of the targeting algorithms that would be used for the main DESI survey, and to stress test the procedures that would be needed for day-to-day DESI operations.…”

Section: Commissioning Survey Validation and The Main Surveymentioning

confidence: 99%

The Target-selection Pipeline for the Dark Energy Spectroscopic Instrument

Myers

Moustakas

Bailey

et al. 2023

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In 2021 May, the Dark Energy Spectroscopic Instrument (DESI) began a 5 yr survey of approximately 50 million total extragalactic and Galactic targets. The primary DESI dark-time targets are emission line galaxies, luminous red galaxies, and quasars. In bright time, DESI will focus on two surveys known as the Bright Galaxy Survey and the Milky Way Survey. DESI also observes a selection of “secondary” targets for bespoke science goals. This paper gives an overview of the publicly available pipeline (desitarget) used to process targets for DESI observations. Highlights include details of the different DESI survey targeting phases, the targeting ID (TARGETID) used to define unique targets, the bitmasks used to indicate a particular type of target, the data model and structure of DESI targeting files, and examples of how to access and use the desitarget code base. This paper will also describe “supporting” DESI target classes, such as standard stars, sky locations, and random catalogs that mimic the angular selection function of DESI targets. The DESI target-selection pipeline is complex and sizable; this paper attempts to summarize the most salient information required to understand and work with DESI targeting data.

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Section: Commissioning Survey Validation and The Main Surveymentioning

confidence: 99%

The Target-selection Pipeline for the Dark Energy Spectroscopic Instrument

Myers

Moustakas

Bailey

et al. 2023

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“…Integration of all of the DESI subassemblies at the Mayall is fully described in Besuner et al (2020).…”

Section: On-site Integration and Installationmentioning

confidence: 99%

“…The corrector has been centered relative to the upper ring. (Image previously published inBesuner et al 2020. )…”

mentioning

confidence: 99%

The Optical Corrector for the Dark Energy Spectroscopic Instrument

Miller,

Doel,

Gutierrez

et al. 2024

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The Dark Energy Spectroscopic Instrument (DESI) is currently measuring the spectra of 40 million galaxies and quasars, the largest such survey ever made to probe the nature of cosmological dark energy. The 4 m Mayall telescope at Kitt Peak National Observatory has been adapted for DESI, including the construction of a 3.°2 diameter prime focus corrector that focuses astronomical light onto a 0.8 m diameter focal surface with excellent image quality over the DESI bandpass of 360–980 nm. The wide-field corrector includes six lenses, as large as 1.1 m in diameter and as heavy as 237 kilograms, including two counterrotating wedged lenses that correct for atmospheric dispersion over zenith angles from 0° to 60°. The lenses, cells, and barrel assembly all meet precise alignment tolerances on the order of tens of microns. The barrel alignment is maintained throughout a range of observing angles and temperature excursions in the Mayall dome by use of a hexapod, which is itself supported by a new cage, ring, and truss structure. In this paper we describe the design, fabrication, and performance of the new corrector and associated structure, focusing on how they meet DESI requirements. In particular, we describe the prescription and specifications of the lenses, design choices and error budgeting of the barrel assembly, stray light mitigations, and integration and test at the Mayall telescope. We conclude with some validation highlights that demonstrate the successful corrector on-sky performance, and we list some lessons learned during the multiyear fabrication phase.

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“…The interlude between these two phases corresponds to the CI campaign, which was described in Section 11.2. See Besuner et al (2020) for a more detailed description of the entire installation process.…”

Section: Integrationmentioning

confidence: 99%

Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Abareshi

Aguilar

Ahlen

et al. 2022

Self Cite

165

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The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z > 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relativity. We describe the significant instrumentation we developed to conduct the DESI survey. This includes: a wide-field, 3.°2 diameter prime-focus corrector; a focal plane system with 5020 fiber positioners on the 0.812 m diameter, aspheric focal surface; 10 continuous, high-efficiency fiber cable bundles that connect the focal plane to the spectrographs; and 10 identical spectrographs. Each spectrograph employs a pair of dichroics to split the light into three channels that together record the light from 360–980 nm with a spectral resolution that ranges from 2000–5000. We describe the science requirements, their connection to the technical requirements, the management of the project, and interfaces between subsystems. DESI was installed at the 4 m Mayall Telescope at Kitt Peak National Observatory and has achieved all of its performance goals. Some performance highlights include an rms positioner accuracy of better than 0.″1 and a median signal-to-noise ratio of 7 of the [O ii] doublet at 8 × 10−17 erg s−1 cm−2 in 1000 s for galaxies at z = 1.4–1.6. We conclude with additional highlights from the on-sky validation and commissioning, key successes, and lessons learned.

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Space-qualified, abuttable packaging for LBNL p-channel CCDs, part II

Cited by 4 publications

References 11 publications

The Target-selection Pipeline for the Dark Energy Spectroscopic Instrument

The Target-selection Pipeline for the Dark Energy Spectroscopic Instrument

The Optical Corrector for the Dark Energy Spectroscopic Instrument

Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

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