Large Surface Light Collector at Mt. Hopkins Observatory, , Smithsonian Institution Archives, (Left to right) Tucson mayor Jim Corbett, Smithsonian Astrophysical Observatory Director Dr. Fred Whipple (1955-1973), and Rep. Morris K. Udall (D-AZ) stand in front of a 34-foot gamma-ray collector at the Smithsonian Astrophysical Observatory, Mt. Hopkins, Arizona. The large surface light collector, really a mosaic of 252 polished glass mirrors, searches for sources of gamma-ray radiation in the heavens, a feat never attempted before from a ground-based observatory..