Observatories on a mountain-top site on the island of Hawaii at a height of 4,200 metres 13,800 feet. It is one of the best sites in the world for optical, infrared and sub-millimetre-wave astronomy and has been developed for this purpose since 1970. The first large telescope to be installed was a 2.24-metre 88-inch reflector of the University of Hawaii. In 1979 three more major telescopes began operation at the observatory: the United Kingdom Infrared Telescope UKIRT, NASA’s Infrared Telescope Facility IRTF and the Canada-France-Hawaii Telescope. The James Clerk Maxwell Telescope working in the millimetre wave region, and the Caltech 10.4-metre 34-foot Submillimeter Array were opened in 1987. The first of the two Keck Observatories was completed in 1992, and the second in 1996. Two 8-metre 26-foot instruments, the Japanese Subaru Telescope and one of the international Gemini Telescopes, are due for completion in 1999.