Active optics is a technology used with reflecting telescopes developed in the 1980s, which actively shapes a telescope's mirrors to prevent deformation due to external influences such as wind, temperature, mechanical stress. Without active optics, the construction of 8 metre class telescopes is not possible, nor would telescopes with segmented mirrors be feasible.
This method is used by, among others, the Nordic Optical Telescope, the New Technology Telescope, the Telescopio Nazionale Galileo and the Keck telescopes, as well as all of the largest telescopes built in the last decade.
Active optics is not to be confused with adaptive optics, which operates at a shorter timescale and corrects different distortions.
Read more about Active Optics: In Astronomy, Other Applications
Famous quotes containing the word active:
“How often must I repeat, that I know or am conscious of my own being; and that I myself am not my ideas, but somewhat else, a thinking, active principle that perceives, knows, wills, and operates about ideas?”
—George Berkeley (1685–1753)