@inproceedings{d443d4360916460bb05cdc974b35361a,
title = "The LFAST 0.76m primary mirrors: mass production, active control and on-sky performance",
abstract = "The Large Fiber Array Spectroscopic Telescope (LFAST) pursues large collecting aperture at low cost. Arrays of 0.76m, f/3.5 mirrors will focus light into fibers that are combined at a high-resolution spectrograph. The mirror substrates are fabricated from 25.4mm thick Schott Borofloat{\textregistered} discs in a one week slump and polish process that leaves less than 80nm rms wavefront error in medium and high spatial frequency modes. Low-order figure errors are corrected with a perimeter ring of thermoelectric controllers that induce expansion or contraction with top-to-bottom thermal gradients. In operation, temperature variations from nighttime cooling cause time-varying aberration modes. Using feedback from a stellar wavefront sensor, these aberrations can be compensated to focus starlight energy into a 1.4 arcsec fiber.",
keywords = "etendue, exoplanet transit spectroscopy, fiber-feed, high-resolution spectroscopy, Peltier device, slumping, telescope arrays, Trizact",
author = "Foster, \{Warren B.\} and Roger Angel and Bender, \{Chad F.\} and Nick Didato and Kevin Gilliam and Peter Gray and Yiyang Huang and Dean Ketelsen and Monson, \{Andrew J.\} and Jason Patrou and Melanie Sisco and Wortley, \{Richard W.\}",
note = "Publisher Copyright: {\textcopyright} 2024 SPIE.; Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI 2024 ; Conference date: 16-06-2024 Through 22-06-2024",
year = "2024",
doi = "10.1117/12.3020505",
language = "English (US)",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Ramon Navarro and Ralf Jedamzik",
booktitle = "Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI",
}