active optics

Quick Reference

A system that compensates for the deforming effects of gravity on a telescope's mirrors, maintaining their surface accuracy and alignment. The image of a guide star is examined as the telescope tracks it across the sky. Actuators behind the mirrors control movable supports to preserve the mirrors' shape and alignment. The first large telescope to employ active optics was the New Technology Telescope at the European Southern Observatory.

Subjects: Astronomy and Astrophysics.

Reference entries