Developments in Large Array Telescopes for Spectroscopic Observations

Abstract

Research of earth like exoplanets in the habitable zone of their host stars may one day confirm there is life outside our solar system. In order to detect biosignatures in the atmospheres of these exoplanets over reasonable time scales (~10 years), a telescope with a tremendously large aperture (~20,000m2) is required. The Large Fiber Array Spectroscopic Telescope (LFAST) is a scalable, unphased, open-air optical telescope array using optical fibers to feed a high resolution spectrograph and is designed especially for the high signal to noise spectroscopy required for future exoplanet research. This thesis investigates the optomechanical design of LFAST’s novel tracking mounts used to steer and co-align the 2640 0.76m diameter sub apertures and evaluate their performance when subject to wind and gravitational flexure. Passive support of the LFAST primary mirrors was also investigated and the design of an 18 point whiffletree-type axial support and central lateral support are discussed. Lastly, LFATS’s method for bringing light together to form a slit poses a potential weakness when performing precision radial velocity measurements, as random telescope dropouts from 1% of the array may produce radial velocity shift of order 2m/s. We explore the use of a rectangular light pipe to homogenize the discrete fiber inputs improving the radial velocity stability of LFAST and improve its resilience to random telescope dropouts by a factor of ~40.