South African Large Telescope
The Southern Africa Large Telescope (SALT) is the largest single optical telescope in the Southern Hemisphere. It can detect stars one billion times dimmer than the faintest star which can be seen with the naked eye. SALT is part of the Southern African Astronomical Observatory near Sutherland, South Africa.
The main mirror is 11 metres in diameter. It is made up of 91 small hexagonal pieces. All the pieces fit together to work like 1 mirror. The light is collected and focused towards one of SALT's science instruments.
SALT points at a fixed angle of 37°. This means is cannot move up and down and can only rotate in a circle. This makes it different from most large telescopes. Instead of moving up and down it uses a tracker system. The tracker moves around the main mirror to collect light from the target object. The tracker allows SALT to collect light from 70% of the night sky. And because the Earth rotates, all objects are visible to SALT at some point during the night.