South African Astronomical Observatory (SAAO)

SAAO is located near the village of Sutherland, at an altitude of 1759 meters. Its biggest telescope is the Southern African Large Telescope (SALT), which is the largest single optical telescope in the southern hemisphere and the largest in Africa. SALT has a hexagonal mirror array 11 meters across, comprised of 91 identical spherical hexagonal segments, and equivalent to a single 10-meter diameter mirror. The telescope is tilted at a fixed angle of 37 degrees from the zenith, so that it moves only in azimuth, rotating into position on air bearings and remaining stationary during each observation. Precise pointing and tracking are handled by the moving optical corrector assembly and instrument payload at the top of the telescope tube. Although based on, and very similar to the Hobby-Eberly Telescope (HET) in Texas, SALT has a redesigned optical system using more of the mirror array. The total telescope cost, including instruments and operation, was US$32 million, of which South Africa contributed a third and the international partners (Germany, New Zealand, Poland, UK and USA) provided the balance. 60% of SALT's construction and development budget has been spent in South Africa.

The 26-m diameter dome and the 34-m high mirror segment alignment tower                                           SALT Control Room                                         

SALT 11-meter primary mirror array. Each mirror segment is 1 meter wide and weighs approximately 100 kilograms.



The 1.9-m (Radcliffe) Telescope was moved to Sutherland in 1974 after 26 years as the main instrument of the Radcliffe Observatory in Pretoria


The 1.9-m Telescope Control Room



The 1.0-m (Elizabeth) Telescope was built by Grubb Parsons in 1964 and erected originally on the SAAO site in Cape Town.
At the time of the move to Sutherland, the Cassegrain f-ratio was changed from f/20 to f/16.



The 1.4-m Infrared Survey Facility (IRSF) belongs to Nagoya University in Japan (left). The Monitoring Network of Telescopes
(MONET) consists of a 1.2-m robotic telescope initiated and coordinated by the University of Gottingen in Germany (right).



Birmingham Solar Oscillations Network (BiSON) is one of six networked solar telescopes spread around the world studying
the 5-minute oscillations of the Sun (left). The 0.75-m Alan Cousins Telescope (ACT) does automatic photometry (right).

Other smaller telescopes at SAAO are the 0.75-m Telescope, the 0.5-m Telescope, and the 0.5-m Yonsei Survey Telescope for Astronomical
Research (YSTAR, not in the photo), which is an international Korean-led effort to monitor variable stars and other transient events.



Art work with ancient references to astronomy in Africa

Royal Observatory at the Cape of Good Hope

The main building (completed in 1828) houses offices and the national library for astronomy

0.61-m f/11 McClean refractor (1897) with 0.46-m f/15 refractor, 16X16 cm plate holders, 203-mm guider, 127-mm f/16 astrometric camera
and Cousins UcBV photometer. With this telescope silicon and europium were first detected in stars other than the Sun, and astrometric and
photometric work continued into the mid-80's.

H.E.S.S.

H.E.S.S. is located in Namibia at an altitude of 1800 meters near the Gamsberg, an area well known for its excellent conditions for optical astronomy. H.E.S.S. is a system of Imaging Atmospheric Cherenkov Telescopes for the investigation of cosmic gamma rays in the 100 GeV energy range. The name H.E.S.S. stands for High Energy Stereoscopic System, and should also remind of Victor Hess, the Austrian who received in 1936 the Nobel Prize in Physics for his discovery of cosmic radiation. The instrument allows exploring gamma-ray sources with intensities at a level of a few thousandth parts of the flux of the Crab nebula. The four 13-m telescopes (of Phase I) of the H.E.S.S. project are arranged in form of a square with 120 m side length; they became operational in December 2003, and were officially inaugurated in September 2004.

The 13-meter mirror is segmented into 382 round mirror facets of 60 cm diameter, made of aluminized glass with a quartz coating. The total mirror area is 108 m² per telescope. In Phase II of the project, a single huge dish with about 600 m² mirror area will be added at the center of the array, increasing the energy coverage, sensitivity and angular resolution of the instrument.

The complete electronics for image digitization, readout and triggering is integrated into the camera body of each telescope. Each camera has a 5^o field of view and consists of 960 photon detector elements (pixels), each subtending 0.16^o angle, using 29 mm, 8-stage photomultiplier tubes with borosilicate windows. Modular construction using 60 drawers which slide into the camera body, with each drawer (photo) containing 16 PMTs and the associated electronics.