Royal Greenwich Observatory, astronomical observatory observatory, scientific facility especially equipped to detect and record naturally occurring scientific phenomena. Although geological and meteorological observatories exist, the term is generally applied to astronomical observatories.
..... Click the link for more information. established in 1675 by Charles II of England; formerly known as the Royal Observatory and located at Greenwich, it moved to Herstmonceux Castle, Sussex, in 1946. In the 1990 new headquarters at Cambridge Univ. were opened. Its equipment includes the 98-in. (248.9-cm) Isaac Newton reflecting telescope, 36-in. (91.4-cm) and 30-in. (76.2-cm) reflecting telescopes, 26-in. (66-cm) and 13-in. (33-cm) refracting telescopes, and an 8-in. (20.3-cm) reversible transit circle. The observatory is administratively responsible for the Radcliffe Observatory, Pretoria, South Africa, where there is a 74-in. (188-cm) reflector. The Royal Greenwich Observatory also includes the Nautical Almanac Office, which publishes the national navigational almanacs, and is responsible for the national time service, on which is based the worldwide system of time zones. The zero meridian, from which longitude is measured, passes through the observatory's former location at Greenwich. Other principal programs include measurement of the proper motions and radial velocities of stars, studies of the dynamics of the solar system and the Milky Way, and studies of the abundances of chemical elements in stars. From the appointment of John Flamsteed as its first director until 1972, the director of the observatory held the title of astronomer royal. Among the noted directors have been Flamsteed, Edmond Halley, James Bradley, Nevil Maskelyne, G. B. Airy, and E. Margaret Burbidge, who was the first director not to be astronomer royal.

Royal Greenwich Observatory

Astronomical observatory, oldest scientific institution in Britain, founded for navigational purposes in 1675 by Charles II at Greenwich, England. Its main contributions have been in navigation, timekeeping, determination of star positions, and almanac publication. In 1767 it began publishing The Nautical Almanac, based on the time at the longitude of Greenwich; its popularity among navigators led in part to the Greenwich meridian's being made Earth's prime meridian and the starting point for international time zones in 1884 (see Greenwich Mean Time).