Code 078 Closed 1971 | Established 1903 | |
Altitude 1,808 metres (5,932 ft) Website assa.saao.ac.za/sections/history/observatories/rep_obs | ||
Union Observatory also known as Johannesburg Observatory (078) is a defunct astronomical observatory in Johannesburg, South Africa that was operated between 1903 and 1971. It is located on Observatory Ridge, the city's highest point at 1,808 metres altitude in the suburb Observatory.
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The observatory and its former annex, the § Leiden Southern Station, are known for the discovery of 6,000 double stars and for Proxima Centauri, made by astronomer Robert Innes. At the observatory, 578 identifications of minor planet were made, a record number at the time. The Minor Planet Center credits the observatory as the site where 147 minor planets were discovered by astronomers Harry Wood, Cyril Jackson, Hendrik van Gent, Ernest Johnson, Ejnar Hertzsprung, Jacobus Bruwer and Joseph Churms (see § List of discovered minor planets).
History
Known as the Transvaal Observatory until 1912, it became the Republic Observatory in 1961. Well remembered for the quality of its Directors, work done on minor planets and the discovery of Proxima Centauri, growing light pollution problems in Johannesburg led to its closure in 1971–1972. The Observatory's buildings at 18a Gill Street, Observatory, Johannesburg, still exist.
At that time the South African government decided to amalgamate all astronomical research into one body, which later became known as the South African Astronomical Observatory (SAAO); it has its headquarters in Cape Town and has Sutherland as its outstation. The main Cape telescopes were moved to Sutherland, and the Radcliffe Observatory at Pretoria was also dismantled.
Leiden Southern Station
The Leiden Southern Station was a collaboration between the Dutch Leiden Observatory and Union Observatory. From 1938 to 1954 it was an annex to the Union Observatory, and was moved to Hartbeespoort in 1954 due to light pollution. It operated until 1978.
List of discovered minor planets
The Minor Planet Center credits Union Observatory ("Johannesburg"), as the site of 147 minor planet discoveries, made by the following list of astronomers: