New generation optical telescopes and plans for a large optical telescope in India

Abstract

The large optical telescopes which are being made now or are under planning differ from the older telescopes in many basic features: the primary mirrors are faster (f/2 or so) and much lighter, the altitude-azimuth mounting is most common, and the enclosures for the telescopes are much smaller and simpler. These changes have been possible due to the advances in computer technology and controls, which make it possible to make intelligent systems based on closed loop control at low costs. The reduction in the overall size of any telescope has naturally led to large savings in the costs, and the new designs of enclosures have minimized the dome seeing effects. The most impressive outcome of the intelligent-system approach has been the implementation of active optics which allows one to get optical aberrations below half seconds of arc. A 4m size telescope which uses many of these modern features is being proposed for our country.