By: Richard Davies

15/11/2000 09:24 - (SA) –Cape Town - A new telescope capable of peering into the depths of our own and neighbouring galaxies to see how stars are born was officially opened at the South African Astronomical Observatory (SAAO) site near Sutherland on Wednesday.

The R18-million InfraRed Survey Facility (IRSF) is the result of an international partnership between Japanese and South African scientists, and will be the second-largest telescope at the observatory, 16km outside the tiny Karoo town. Utilising a 1,4-metre diameter mirror, the facility will be able to "see" infrared radiation and record images on a specially-built R7-million camera.

Infrared radiation has the power of penetrating haze and dust clouds, which scatter ordinary visible light. "We can't see infrared radiation, but we may feel it as heat," said SAAO director Dr Bob Stobie. "At these wavelengths we can see through dust clouds to regions otherwise hidden from our view." "Infrared light is also ideal for studying cool stars that radiate most of their energy at wavelengths too long for the eye to see," he said. Major funding for the project comes from Japan's ministry of education. Nagoya University built the infrared "Sirius" camera, and the institution's staff worked with an optical company in Kyoto to build the telescope itself, which uses Russian optics. SAAO senior astronomer Dr Ian Glass told a media briefing in Cape Town that infrared observations made to date had been very shallow, and the time was ripe for a deep survey. The IRSF's main targets would be the two galaxies nearest to our own – the greater and small Magellanic Clouds - and the central region of our own Milky Way galaxy.

The man in charge of the Japanese side of the project, Dr Tetsuo Hasegawa of the University of Tokyo, said the unveiling of the IRSF at Sutherland was the realisation of a long-standing dream for astronomers in his country. "The centre of the Milky Way galaxy can only be seen at an angle of 25 degrees above the horizon in Japan." The observatory at Sutherland was much better positioned to study this portion of the night sky. Hasegawa said data from an infrared study of the Magellanic Clouds and our own galactic centre would give astronomers a better understanding of how stars were formed. "With the Sirius camera, stars 100 times fainter than those seen before can be photographed." Astronomers knew that in the Magellanic Clouds, stars were born in clusters or groups, while in our own Milky Way galaxy they appeared to be formed individually. Data collected from IRSF over the next few years would enable researchers to explain this difference, and to construct a scientific model explaining star formation. Results could also be compared with data obtained from radio telescopes, he said. In each infrared photographic exposure made at Sutherland, an area of the sky - a square about one quarter as wide as the full Moon - will be simultaneously recorded in three different infrared wavebands. According to Hasegawa, the new facility will be "taking pictures within a matter of weeks".

National Research Foundation president Dr Khotso Mokhele, who presided over Wednesday's opening ceremony, said the IRSF ushered in an exciting new era for infrared astronomy.

The opening of the IRSF follows hot on the heels of a groundbreaking ceremony at the Sutherland site two months ago to mark the start of construction on the Southern African Large Telescope (Salt). Costing R100-million to erect over the next five years, Salt will be the biggest telescope in Africa and powerful enough to detect a light source the size of a candle flame as far away as the moon, or to resolve the shape of an object the size of a two rand coin at a distance of ten kilometres.

Observers believe the work - specifically the Salt and IRSF initiatives - being carried out in the heart of the Karoo over the next five years will place South Africa on the cutting edge of international astronomy. Scientific spin-offs from the Salt project alone are expected to have a huge impact locally in the fields of optics, mechanical design, robotics, data reduction, computer networking and cryogenics, among others. – Sapa

Submitted by Brian Fraser