Royal Greenwich
Observatory was established by Charles II in 1675 at Greenwich and transferred to Herstmonceux Castle, near
Halisham, Sussex, England, after World War II. Its first two directors were John Flamsteed and Edmond Halley; the third director, James Bradley, discovered (1784) the nutation of the Earth. In 1884 the meridian (0¡ longitude) at Greenwich was chosen the world's prime meridian, from which east-west longitude and time zones are calculated (see also Greenwich mean time). Instruments at the site included a photographic zenith tube (1955), a 36-in (91-cm) Yapp reflecting telescope (1932), and a 38-in (96-cm) Hargreaves reflector (1972). The
observatory's 98-in (2.5-m) Isaac Newton telescope,
completed in 1967, was moved to the island of La Palma in the Canary Islands and began operating there in 1984; the observatory also constructed its 165-in (4.2-m) William Herschel telescope at this site. In 1986 the decision was made to transfer the remaining facilities and all operations of the Royal Greenwich Observatory to Cambridge University, a move completed in 1990. In October 1998, however, after more than 300 years, the facility was forced to close because of budget cuts.