Performance Impacts for Actuator Misalignments and Failures in Large-ApertureAdaptive-Optic Telescopes

摘要

Large-aperture telescopes require adaptive optics in order to compensate foratmospheric turbulence which would otherwise negate the resolution advantages of using large apertures. This investigation analyzes the impacts of misalignments and failures, in the deformable mirror actuators, upon the performance of such systems. A numerical simulation of a standard adaptive optics system is used to generate characteristic optical transfer function (OTF) and signal-to-noise ratio (SNR) performance metrics. The performance impacts of the misalignments are shown to be dependent upon the Fried parameter (effective telescope diameter), the source object brightness, and the control system time delay. The degree of performance degradation is directly related to the relative value of the Fried parameter to the deformable mirror displacement (misalignment cases) and the effective actuator spacing (actuator failure cases). The results indicate that the impact of misalignments and failures is small when seeing conditions are good or the percentage misalignments and failures are small.