Keck Telescope

World's second-largest optical telescope, situated on Mauna Kea, Hawaii. It has a primary mirror 10 m/33 ft in diameter, unique in that it consists of 36 hexagonal sections, each controlled and adjusted by a computer to generate single images of the objects observed; it weighs 331 tons and became fully operational in 1992. It received its first images in 1990 and was superseded as largest optical telescope by the Great Canary Telescope (GCT) in 2007.

An identical telescope next to it, named Keck II, became operational in 1996. Both telescopes are jointly owned by the California Institute of Technology, Pasadena, and the University of California's Lick Observatory, Mount Hamilton.