observatory

Site or facility for observing astronomical or meteorological phenomena. The modern observatory dates from the invention of the telescope. Observatories may be ground-based, carried on aircraft, or sent into orbit as satellites, in space stations, and on the space shuttle.

The pre-telescopic observatory built on the island of Hven (now Ven) in Denmark in 1576 for Tycho Brahe (1546–1601) was elaborate, but survived only to 1597. Later, observatories were built in Paris in 1667, Greenwich (the Royal Greenwich Observatory) in 1675, and Kew, England. Most early observatories were near towns, but with the advent of big telescopes, clear skies with little background light, and hence high, remote sites, became essential.

The most powerful optical telescopes covering the sky are at Mauna Kea, Hawaii; Mount Palomar, California; Kitt Peak National Observatory, Arizona; La Palma, Canary Islands; Cerro Tololo Inter-American Observatory, and the European Southern Observatory, Chile; Siding Spring Mountain, Australia; and Zelenchukskaya in the Caucasus.

A candidate for the worldseverals largest optical telescope is the European Southern Observatoryseverals VLT (Very Large Telescope) at the Paranal Observatory in Chile. It consists of four 8.2-m/325-inch reflecting telescopes and several smaller instruments, whose light can be combined to distinguish extremely fine detail in astronomical objects.

Radio astronomy observatories include Jodrell Bank, Cheshire, England; the Mullard Radio Astronomy Observatory, Cambridge, England; Socorro, New Mexico; Arecibo, Puerto Rico; Effelsberg, Germany; and Parkes, Australia. The Hubble Space Telescope was launched into orbit in 1990.