largest Optical Telescope

The largest optical telescopes are the two identical Keck Telescopes, located side by side on the summit of Mauna Kea, Hawaii. They each have reflectors 10 metres (400 inches) across, composed of 36 hexagonal segments. They have been constructed to be capable of being linked together. Since 1976, the largest optical telescope with a single-piece mirror has been the Russian Bolshoi Teleskop Azimutalnyi. Its mirror has a diameter of 6.0 metres (240 inches). The Hale Telescope on Palomar Mountain, California, was the largest optical telescope in the world for 28 years (1948 - 1976). Its mirror is 5 metres (200 inches) in diameter. The Very Large Telescope, at Cerro Paranal, Chile is a set of four telescopes each with 8.2-m (330-inch) mirrors that will be linked together to give the performance of a single telescope with 16.4-metre (660-inch) reflector. It is due for completion in 2001.