An automatic system for keeping a reflecting surface in a telescope free from distortion due to gravity or other environmental effects, using small pistons which continuously adjust the position of each part of the surface.
Origin
1960s.
Definition of active optics in US English:
active optics
noun
Astronomy
An automatic system for keeping a reflecting surface in a telescope free from distortion due to gravity or other environmental effects, using small pistons which continuously adjust the position of each part of the surface.