Ground Telescopes

South African Large Telescope

At 11 metres in diameter, the Southern Africa Large Telescope (SALT) is the largest single optical telescope in the southern hemisphere, able to detect stars one billion times dimmer than the faintest visible to the unaided eye. It is sited at the Southern Africa Observatory site near Sutherland, Northern Cape.

The main mirror, however, is not one single piece of glass, but made up of 91 hexagonal mirror segments which are all carefully joined and aligned to reflect the light as if they were one mirror.

Anglo-Australian Telescope

Commissioned way back in 1974, the Anglo-Australian Telescope was one of the last 4 metre equatorially mounted telescopes to be constructed. Such telescopes are tilted to align with the rotation of the Earth, and follow or track a star through the sky they only have to move in one direction. Most modern large telescopes have to move in two directions to follow a star - a more complicated technique but possible these days with the advent of modern computers.