Astrophysics (Index)About

Large Altazimuth Telescope

(BTA-6, Bol'shoi Teleskop Azimultal'nyi)
(6-meter reflector telescope in Russia)

The Large Altazimuth Telescope (BTA-6 or Bol'shoi Teleskop Azimultal'nyi) is a 6-meter reflector telescope in southern Russia, that began operation in 1975 and was the world's largest optical telescope until Keck's 1990 first light.

BTA-6 has a monolithic mirror and is of the Ritchey-Chrétien telescope design. It has an altazimuth mount and was a pioneer in using such a mount under computer control for a large research telescope. Over much of BTA-6's life, it has had mirror flaws, with a third mirror installed in 1978 and used until 2018, when the second mirror was reinstalled after substantial regrinding to eliminate its problems.


Further reading:

Referenced by pages:
Hale Telescope
monolithic mirror
segmented mirror