SALT: Africa's eye on the universe
5 May 2005
Construction of the US$30-million Southern African Large Telescope (SALT) - at 11 metres in diameter the largest in the southern hemisphere - is well advanced at the SA Astronomical Observatory in Sutherland in the remote Northern Cape, with the official opening set for 11 November.
The telescope will undergo performance verification from June. The results of its first observations, made in October 2004, showed that the telescope had ample light-gathering power to be scientifically useful, despite having less than half of its 91 mirrors installed at that stage.
With a hexagonal mirror array 11m across, SALT will be one of the leading instruments of its kind, enabling local and international scientists to see distant stars, galaxies and quasars a billion times too faint to be visible to the naked eye - as faint as a candle's flame at the distance of the moon.
The completed telescope will be similar to the Hobby-Eberly Telescope in Texas in the
US, but will have a redesigned optical system that uses more of the mirror array.
This means that the series of mirrors will correct distortions and aberrations in the light collected by the telescope more accurately than the Hobby-Eberly mirror array - an achievement of South African astronomer Dr Darragh O'Donoghue.
SALT's shareholders are South Africa's National Research Foundation (34.4%), Dartmouth College (14%), the University of Wisconsin-Madison (14%), the Nicolaus Copernicus Astronomical Centre of the Polish Academy of Sciences (11%), Rutgers University (10%), the UK SALT Consortium (4%), the University of Canterbury (4%), Goettingen University (4%), Carnegie-Mellon University (3%) and the University of North Carolina (3%).
Further partners may join once SALT becomes operational; Canada, Japan and astronomers from California have reportedly expressed interest.
About 60% of SALT's components were made in South Africa, including the aluminium dome, put
together by BKS Advantech.
The mirror segment mounts are an American design, but have been made by a South African company, Schuurman Engineering. Another local company, Special Products Technologies, was responsible for the mirror coating plant, which coats the mirror segments with aluminium.
SALT's remote location will help provide better images from space. In this 2002 photo, a giant crane completes the placement of the frame for SALT's giant dome.
More expensive items have come from abroad - including mirrors from Russia, mirror figuring from Kodak in the US, the edge sensing system from France, the alignment system from the US, and the actuators from Germany.
According to SALT project manager Kobus Meiring, funding of $18.5-million for the construction of the telescope, and $4.8-million for scientific instrumentation, has been secured, in addition to funding for
seven-and-a-half out of 10 solicited years for operations.
Meiring told Engineering News that, wherever possible, companies from the Cape area had been used for all mechanical contracts. However, he added, SALT's long-term benefits - apart from the obvious scientific ones - would lie in tourism.
There are regular tours of the SA Astronomical Observatory, but, Meiring told Engineering News, "we need to improve visitors' access to a telescope or a number of telescopes at night to encourage them to stay overnight in the town".
Other long-term benefits could come the way of SALT suppliers, who could find opportunities to be involved in other large telescope projects.
SouthAfrica.info reporter
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