How “adaptive optics” reduce the effects of atmospheric distortion

A computer-controlled mirror with a surface that can change shape reacts continuously to incoming rays’ constantly shifting angles. The computer samples the distortions of the atmosphere and tells the mirror what shape to take to keep all the rays aimed at one focal point. The mirror is in constant motion. At right are three sample snapshots of the mirror in motion. One single, stable point of focus is achieved, resulting in a clear image.