Sky & Telescope April 1984 [antikvár]

Schmidt Views of the Southern SkyRussell Cannon, Royal Observatory, EdinburghT WO HUNDRED MILES from the city lights of Sydney, Australia, lies the town of Coonabarabran. There is little to distinguisi! it from hundreds of other frontier crossroads scattered over the continent except for a winding road that leads westward through the rugged War-rumbungle National Park. Kangaroos graze and frolic along the road, which after some 17 miles leads travelers to a hilly plateau (Siding Spring Mountain) some 3,700 feet above sea level.There, towering over the trees and brush, stand severa! gleaming domes of various sizes, connected by stretches of pavement that wind among them. One dome tops a squat, compact building along the plateau's northern rim. But this facili-ty's small size is deceptive, for it houses the United Kingdom's 1.25-meter (49-inch) Schmidt telescope the largest of its kind in the Southern Hemisphere.The UKST, as i»s called, is actually a field station of the Royal Observatory, Edinburgh, Scotland, which in turn is di-rected by the United Kingdom's Science and Engineering Research Council. Be-cause of their remoteness, the instruments on Siding Spring Mountain enjoy night skies almost completely free from light pol-lution, a critical factor for optimal use of the big Schmidt's fast (f/2.5) optical sys-tem. However, such isolation also requires a certain degree of self-sufficiency, and the UKST's six or seven resident astronomers usually move to Australia with their families for three-year tours of research.Astronomers obtained the first fully suc-cessful deep-sky plate with the UKST on September 3, 1973. Perhaps a harbinger of future rewards, even that first plate pro-duced exciting astronomical results (faint jets of light attending the galaxy NGC 1097). In the succeeding 10 years, UKST observers have taken nearly 9,000 photo-graphs, carried out hundreds of research projects, and are nearing the completion of two major sky surveys.Built by Grubb Parsons, Ltd., this classic Schmidt has a 49-inch clear aperture,72-inch spherical primáry mirror, and 121-inch focal length. It obtains photographs 14 inches (6Vi°) on a side, yielding a plate scale of 67.1 are seconds per millimeter. These parameters match those of the fa-mous Schmidt telescope on Palomar Mountain in California, which was built 25 years earlier. However, the UKST takes full advantage of improved telescope design and photographic emulsions, making it considerably more powerful than its predecessor. For example, slewing, fieldAbooe: Opened for business in 1973, the dome and building of the United Kingdom Schmidt Telescope (at right) overlook War-rumbungle State Park in New South Wales, Australia. Insets: Although the observatory is very remote, astronomers there are well-equipped to analýze its photographic boun-ty. The UKST's 49-inch aperture makes it the world's third-largest Schmidt, and the largest in the Southern Hemisphere. Photographs were supplied by the author; un-less noted otherwise, they are copyright Royal Observatory, Edinburgh (ROE).