SALT: Africa's eye on the universe

10 November 2005

President Thabo Mbeki officially inaugurated the R200-million (US$36-million) Southern African Large Telescope (SALT) at the South African Astronomical Observatory in Sutherland in the remote Northern Cape on Thursday.

With a hexagonal mirror array 11 metres in diameter, the telescope is the largest in the southern hemisphere and among the 10 biggest in the world.

Speaking at the inauguration ceremony, Mbeki said that SALT - South Africa's biggest investment in astronomy to date - would both benefit the international community and ensure that South Africa remained at the cutting edge of astronomy.

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 telescope is similar to the Hobby-Eberly Telescope in Texas in the US, but has a redesigned optical system - an achievement of South African astronomer Dr Darragh O'Donoghue - that uses more of its mirror array.

This means that its series of 91 mirrors, each a metre wide and weighing approximately 100 kilograms, will correct distortions and aberrations in the light collected by the telescope more accurately than the Hobby-Eberly mirror array.

The SALT project is a collaboration between research institutions in South Africa, the United States, United Kingdom, Germany, Poland and New Zealand.

According to Business Day, South Africa contributed about one-third of the R200-million construction costs. About 60% of SALT's components, including the aluminium dome, were made in South Africa.

SALT's operational model, with South African Astronomical Observatory staff operating the telescope on behalf of SALT's international partners, will make SALT more like a space-based telescope, like the Hubble Space Telescope, than its ground-based cousins.

"SALT was an initiative of South African astronomers that won support from the South African government, not simply because it was a leap forward in astronomical technology, but because of the host of spin-off benefits it could bring to the country", said project scientist David Buckley.

"Indeed, the SALT project has become an iconic symbol for what can be achieved in science and technology in the new South Africa."

SouthAfrica.info reporter