September 2, 2005, near Sutherland, South Africa--Exactly five years after groundbreaking, the Southern African Large Telescope (SALT) project has released its first color images, marking the achievement of 'first light' and the successful debut of full operation for SALTICAM, a $600,000 digital camera designed and built for SALT at the South African Astronomical Observatory (SAAO). SALT is the largest optical telescope in the southern hemisphere, and equal to the largest in the world.
Gathering more than 25 times as much light as any existing African telescope, SALT can detect objects as faint as a candle flame on the moon. The sample images now released for the first time were taken during the camera's first trial period of operation, which also achieved SALT's first significant scientific results.
A major recent milestone was the installation in May of the last of the 91 hexagonal mirror segments that comprise SALT's mammoth primary mirror array, stretching 11-m across. Limited scientific observations have already begun with SALT while completion of the
telescope's commissioning continues over the coming months. In the next month or so, installation will begin of the major first generation instrument, the Prime Focus Imaging Spectrograph (designed and built for SALT by the University of Wisconsin-Madison and Rutgers University).
No longer will it be necessary for astronomers in the consortium to travel to SALT to use it. Instead they will submit their observing requests over the Internet and eventually, once the observations have been conducted by the dedicated SALT operations staff, they will also
receive their data over the Internet. In many respects this makes SALT far more like a space-based telescope, like the Hubble Space Telescope, than its ground-based cousins.
The images shown at http://www.salt.ac.za/content/first_light/index.html are a first indication of SALT's capabilities. While the imaging quality is not yet at its final optimal value, the sheer light gathering power of the telescope is amply demonstrated in these images. Most of the color images were produced by combining separate images in three filters: ultraviolet (U), visible (V) and infrared (I), each with an exposure time typically of 10 to 120 seconds. The galaxy image (NGC6744) was made by combining ultraviolet, blue and infrared images. Eventually the sharpness of SALT's images will be improved by the full implementation of its active optics control, although this is not yet operational.