The optical design for the Giant Magellan Telescope Multi-object Astronomical and Cosmological Spectrograph (GMACS) Conference Paper uri icon


  • © 2018 SPIE. We describe the optical design of GMACS, a multi-object wide field optical spectrograph currently being developed for the Giant Magellan Telescope (GMT). Optical spectrographs for the emerging generation of Extreme Large Telescopes (ELTs) have unique design issues. For example, the combination of both the largest field of view practical and beam widths achieving the desired spectral resolutions force the design of seeing limited ELT optical spectrographs to include large refractive elements, which in turn requires a compromise between the optical performance, manufacturability, and operability. We outline the details of the GMACS optical design subsystems, their individual and combined optical performance, and the preliminary flexure tolerances. Updates to the detector specifications, field acquisition/alignment optics, and optical considerations for active flexure control are also discussed. The resulting design meets the technical instrument requirements generated from the GMACS science requirements, is expected to satisfy the available project budget, and has an acceptable level of risk for the subsystem manufacture and assembly.

author list (cited authors)

  • Ribeiro, R., Schmidt, L. M., Jones, D., Taylor, K., Prochaska, T., Cook, E., ... Souza, A.

citation count

  • 1

publication date

  • July 2018