Segmented mirror
array of smaller mirrors acting together as a single, large mirror
A segmented mirror is an array of smaller mirrors designed to act as segments of a single large curved mirror. The segments can be either spherical or asymmetric (if they are part of a larger parabolic reflector). They are used as objectives for large reflecting telescopes. To function, all the mirror segments have to be polished to a precise shape and actively aligned by a computer-controlled active optics system using actuators built into the mirror support cell.
The concept was pioneered by Guido Horn D'Arturo, who built the first working segmented mirror in 1952, after twenty years of research; It was later independently rediscovered and further developed under the leadership of Dr. Jerry Nelson at the Lawrence Berkeley National Laboratory and University of California during the 1980s, and since then all the necessary technologies have spread worldwide to the point that essentially all future large optical telescopes plan to use segmented mirrors.
Application
There is a technological limit for primary mirrors made of a single rigid piece of glass. Such non-segmented, or monolithic mirrors can not be constructed larger than about eight meters in diameter. The largest monolithic mirrors in use are currently the two primary mirrors of the Large Binocular Telescope, each with a diameter of 8.4 meters. The use of segmented mirrors is therefore a key component for large-aperture telescopes.
“Segmented mirror” enters the record as array of smaller mirrors acting together as a single, large mirror. Crown Archives preserves that source wording while asking what Segmented, mirror and array can confirm, complicate or overturn.
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This entry incorporates text from “Segmented mirror” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.