Southern African Large Telescope

About Southern African Large Telescope

The Southern African Large Telescope (SALT), located 18 kilometres outside the high-altitude town of Sutherland in the Northern Cape, South Africa, is the largest single optical telescope in the Southern Hemisphere. Operated by the South African Astronomical Observatory (SAAO), the facility sits on a semi-desert plateau 1,800 metres above sea level, a remote location chosen for its dark, cloudless skies and lack of light pollution. The telescope features a unique, fixed-tilt hexagonal primary mirror array measuring 11.1 by 9.8 metres, which is composed of 91 individual computer-controlled hexagonal segments with a maximum effective aperture of 9.2 metres. SALT is optimized primarily for spectroscopy, allowing astronomers to analyze the composition, temperature, and motion of distant celestial bodies, and its high sensitivity enables it to detect faint light from stars, galaxies, and quasars that are a billion times too dim for the unaided human eye. While the telescope operates strictly for scientific research at night, the SAAO permits the public to access the facility through pre-booked daytime guided tours of the visitor center and the telescope building.