The Large Fiber Array Spectroscopic Telescope: optical design of the unit telescope
Affiliation
Steward Observatory, University of ArizonaJames C. Wyant College of Optical Sciences, University of Arizona
Issue Date
2022Keywords
atmospheric dispersion correctionLarge telescopes
LFAST
optical design
spectroscopic telescopes
Metadata
Show full item recordPublisher
SPIECitation
Berkson, J., Angel, R., Bender, C., Young, A., & Gray, P. (2022). The Large Fiber Array Spectroscopic Telescope: Optical design of the unit telescope. Proceedings of SPIE - The International Society for Optical Engineering, 12182.Rights
Copyright © 2022 SPIE.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
The concept for the Large Fiber Array Spectroscopic Telescope (LFAST) (Angel et al, these proceedings) is to collect the light from a target object using thousands of individual, small, low-cost telescopes, and bring it via optical fibers to a high resolution (R=150,000) spectrograph. Each mirror has a prime focus corrector feeding a 17 micron fiber at f/3.5, subtending a 1.3 arcsec diameter on the sky. Each LFAST unit has 20 separate 30 inch telescopes carried by a single alt-az mount to provide collecting area equivalent to a 3.5 m traditional aperture. Each mirror has a 4-element corrector provides subarcsecond imaging over an 8 arcmin field. The field is reflected by a mirror puck (which contains the receiving fiber) through relay optics to a CMOS camera for rapid guiding and wavefront measurement. The corrector optical design incorporates elements of common crown and flint glass to obtain achromaticity over a broad wavelength range of 380 nm-1700 nm. Large, slow lateral translations of the final 4th element correlated with primary mirror tilt correct for atmospheric dispersion, and small, rapid lateral translations correct for image motion without significantly disrupting atmospheric dispersion correction. We have explored both aspherical and spherical primary mirror designs and have chosen spherical, based on impacts to unit telescope cost. © 2022 SPIE.Note
Immediate accessISSN
0277-786XISBN
9781510653450Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1117/12.2628816