Design of the Southern African Large Telescope (SALT)

SALT is a 10-m class telescope for optical/infrared astronomy to be sited at Sutherland, the observing state of the South African Astronomical Observatory. This telescope will be based on the principle of the Hobby-Eberly Telescope (HET) at McDonald Observatory, Texas. This cost-effective design is a tilted-Arecibo concept with a segmented spherical primary mirror of diameter 11 meters. The telescope has a fixed gravity vector but with full 360 degrees rotation in azimuth. A spherical aberration corrector mounted on a tracker beam at the prime focus enables a celestial object to be followed for 12 degrees across the sky. The SALT design enables over 70% of the sky to be accessed for about 20% of the cost of a conventional telescope of similar aperture. The telescope will be used primarily for spectroscopic studies of celestial objects with a light-weight low-dispersion imaging spectrograph mounted at the prime focus and other higher-dispersion instruments fiber-fed and mounted in an environmentally controlled basement. The concept design for SALT is presented with emphasis on the design changes between SALT and HET.