The Astronomical Journal (Jan 2024)

Measuring Fiber Positioning Accuracy and Throughput with Fiber Dithering for the Dark Energy Spectroscopic Instrument

  • E. F. Schlafly,
  • D. Schlegel,
  • S. BenZvi,
  • A. Raichoor,
  • J. E. Forero-Romero,
  • J. Aguilar,
  • S. Ahlen,
  • S. Bailey,
  • A. Bault,
  • D. Brooks,
  • T. Claybaugh,
  • K. Dawson,
  • A. de la Macorra,
  • Arjun Dey,
  • P. Doel,
  • E. Gaztañaga,
  • S. Gontcho A Gontcho,
  • J. Guy,
  • C. Hahn,
  • K. Honscheid,
  • J. Jimenez,
  • S. Kent,
  • D. Kirkby,
  • T. Kisner,
  • A. Kremin,
  • A. Lambert,
  • M. Landriau,
  • M. E. Levi,
  • M. Manera,
  • P. Martini,
  • A. Meisner,
  • R. Miquel,
  • J. Moustakas,
  • A. D. Myers,
  • J. Nie,
  • N. Palanque-Delabrouille,
  • W. J. Percival,
  • C. Poppett,
  • F. Prada,
  • D. Rabinowitz,
  • M. Rezaie,
  • G. Rossi,
  • E. Sanchez,
  • M. Schubnell,
  • R. Sharples,
  • J. Silber,
  • G. Tarlé,
  • B. A. Weaver,
  • Z. Zhou,
  • H. Zou,
  • DESI Collaboration

DOI
https://doi.org/10.3847/1538-3881/ad4d8c
Journal volume & issue
Vol. 168, no. 1
p. 35

Abstract

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Highly multiplexed, fiber-fed spectroscopy is enabling surveys of millions of stars and galaxies. The performance of these surveys depends on accurately positioning fibers in the focal plane to capture target light. We describe a technique to measure the positioning accuracy of fibers by dithering fibers slightly around their ideal locations. This approach also enables measurement of the total system throughput and point-spread function delivered to the focal plane. We then apply this technique to observations from the Dark Energy Survey Instrument (DESI), and demonstrate that DESI positions fibers to within 0.″08 of their targets (5% of a fiber diameter) and achieves a system throughput within about 7% of expectations.

Keywords