Active and adaptive optics History of the telescope

the 1980s saw introduction of 2 new technologies building larger telescopes , improving image quality, known active optics , adaptive optics. in active optics, image analyser senses aberrations of star image few times per minute, , computer adjusts many support forces on primary mirror , location of secondary mirror maintain optics in optimal shape , alignment. slow correct atmospheric blurring effects, enables use of thin single mirrors 8 m diameter, or larger segmented mirrors. method pioneered eso new technology telescope in late 1980s.

the 1990s saw new generation of giant telescopes appear using active optics, beginning construction of first of 2 10 m (390 in) keck telescopes in 1993. other giant telescopes built since include: 2 gemini telescopes, 4 separate telescopes of large telescope, , large binocular telescope.

eso s vlt boasts advanced adaptive optics systems, counteract blurring effects of earth s atmosphere.

adaptive optics uses similar principle, applying corrections several hundred times per second compensate effects of rapidly changing optical distortion due motion of turbulence in earth s atmosphere. adaptive optics works measuring distortions in wavefront , compensating them rapid changes of actuators applied small deformable mirror or liquid crystal array filter. ao first envisioned horace w. babcock in 1953, did not come common usage in astronomical telescopes until advances in computer , detector technology during 1990s made possible calculate compensation needed in real time. in adaptive optics, high-speed corrections needed mean bright star needed close target of interest (or artificial star created laser). also, single star or laser corrections effective on narrow field (tens of arcsec), , current systems operating on several 8-10m telescopes work in near-infrared wavelengths single-object observations.

developments of adaptive optics include systems multiple lasers on wider corrected field, and/or working above kilohertz rates correction @ visible wavelengths; these in progress not yet in routine operation of 2015.