Innovative pupil topographies for sparse aperture telescopes and SNR

Abstract

Since the first application of the telescope to astronomy in 1610, most new astronomical discoveries require larger and larger radiation collecting areas. Today, the twin 10-meter Keck telescopes are operational and several 30-meter-aperture class telescopes are being planned. Optical interferometers and sparse aperture ground telescopes for astronomy have been proposed and built. Fienup showed the dependence between exposure time and the dilution factor of the aperture needed to maintain image quality.1 Carpenter suggests a sparse aperture telescope system for the purpose of imaging across the surfaces of stars.2 This paper demonstrates that the ability to reconstruct images from white-light extended sources with different contrast levels also depends on the specific pupil topography that is applied to the telescope system. Signal-to-noise ratios for recorded images are calculated for scene contrast, pupil shape, detector full-well, detected photons, and exposure times.