The origins of the observatory began when Theodore Reunert of the South African Association for the Advancement of Science petitioned
Alfred Milner Governor of the
Transvaal Colony on 29 October 1902 for the establishment of a meteorological and astronomical observatory in Johannesburg. Assistant Colonial Secretary W.H. Moor agreed to the project on 17 December 1902 with the budget increased from £1,350 to £5,629 due to equipment changes. On 1 April 1903, a new Meteorological Department was temporarily established in
Johannesburg. A location was sought for the new observatory and the Johannesburg Town Council made a decision on 12 May 1903, located within the municipal boundaries. The land of eight acres, on a ridge west of the Indian War Memorial, was on the northern boundary of the farm
Doornfontein, presently part of the suburb
Observatory and was given as a gift by the Bezuidenhout family, with a further two acres sold for £500. The land was given only for the use of science and a road, later called Observatory Avenue, was also to be built close to the site. The observatory building was built and the formal opening took place on 17 January 1905 by Governor Milner, but had no astronomical equipment. In 1906 it was lent a Hamberg universal instrument (2 5/8-inch object glass) by Dr
Oskar Backlund. In September 1907 a 9-inch Grubb refractor was now used but repolished in 1908. Mr J. Franklin-Adams gifted the observatory a 10-inch triple O.G. Cooke Star-Camera in 1909. J.B. Rissik, Minister for Lands, permitted the purchase of a 26-inch refracting telescope from the
Grubb Telescope Company in 1909. With the formation of the Union of South Africa in 1910, South Africa's two colonial observatories came under the control of the Minister of the Interior. With the removal of the meteorological functions, the observatory was renamed Observatory of the Union of South Africa (Union Observatory) on 1 April 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. The main-belt asteroid
1585 Union, discovered by
Ernest Johnson in 1947, was named for the Union observatory.
Name changes Union Observatory went through a number of name changes: • 1903–1909: Transvaal Meteorological Department • 1909–1912: Transvaal Observatory • 1912–1961: Union Observatory • 1961–1971: Republic Observatory
Directors Its directors were: • 1903–1927:
Robert Innes • 1927–1941:
Harry Edwin Wood • 1941–1956:
Willem Hendrik van den Bos • 1957–1965:
William Stephen Finsen • 1965–1971: Jan Hers (1915–2010) == Leiden Southern Station ==