The Optical Corrector for the Dark Energy Spectroscopic Instrument

Abstract 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°…

• NS
  National Science Foundation

  Awards: Contract No. AST-0950945, AST-0950945, DE-AC02-07CH11359, DE-AC02-05CH11231, 0950945
• UD
  U.S. Department of Energy

  Awards: -AC02-05CH11231, DE-AC02-07CH11359, 05CH11231, AC02-07CH11359, AC02-05CH11231, DE-AC02, DE-AC02-05CH11231, DE-AC02-
• GA
  Gordon and Betty Moore Foundation
• HF
  Heising-Simons Foundation

  Award: 2014-91
• NE
  National Energy Research Scientific Computing Center

  Award: Contract No. DE-AC02-05CH11231
• MD
  Ministerio de Ciencia e Innovación
• CÀ
  Commissariat à l'Énergie Atomique et aux Énergies Alternatives
• OO
  Office of Science

  Awards: AC02-05CH11231, -AC02-05CH11231, DE-AC02, DE-AC02-07CH11359, Contract No. DE-AC02-05CH11231
• SA
  Science and Technology Facilities Council

  Awards: DE-AC02-07CH11359, ST/M00287X/1, ST/M00287X/1
• DO
  Division of Astronomical Sciences

  Award: AST-0950945
• F
  Fermilab