A deformable secondary demonstrator for adaptive optics

TLDR: In this paper, the authors describe the design, simulation, construction, and laboratory evaluation of a large adaptive secondary mirror for 8m class telescopes and assess the viability of the approach of large adaptive secondaries for 8 m class telescopes.

Abstract: Atmospheric turbulence distorts the wavefront of the incoming light from an astronomical object and so limits the ability of a telescope to form perfect images. Adaptive optics is a combination of technologies that enable the correction of the wavefront distortion in real time. Conventional adaptive optics operate like auxiliary instruments and use additional relay optics which reduce total throughput and introduce extra IR emissivity and polarisation. Adaptive secondary mirrors avoid additional optical surfaces by providing the optical correction at an existing telescope surface (the secondary mirror). Previous studies have demonstrated the optical efficacy and mechanical feasibility of performing the adaptive correction in this way. A demonstrator is being developed to explore features and techniques applicable to a large adaptive secondary mirror and to explore manufacturing, assembly/disassembly, calibration and measurement techniques. This thesis describes the design, simulation, construction, and laboratory evaluation of the demonstrator. The thesis concludes with assessment of the viability of the approach of large adaptive secondaries for 8-m class telescopes.