Effects of wavefront sampling speed on the performance of adaptive astronomical telescopes

Adaptive imaging systems have been developed to compensate for distortions introduced by atmospheric turbulence. Their performance is limited by the wavefront sampling rate which is constrained by the wavefront sensor processing time. This paper explores the degradation of system performance caused by limitations in the wavefront sampling rate. Errors introduced by finite image observation times are also examined. For bright images, a very short observation time per sampling period is shown to yield high system resolution. For the case of very faint images, continuous observation results in the best signal-to-noise ratio. Adaptively correcting a 4-m telescope is shown to improve the detection threshold by nearly three visual magnitudes.