Union Observatory

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.[1][2]

Union Observatory
Alternative namesJohannesburg Observatory
Observatory code 078 
LocationObservatory, City of Johannesburg Metropolitan Municipality, Gauteng, Transvaal region
Coordinates26°11′3″S 28°04′27″E
Altitude1,808 metres (5,932 ft)
Established1903
Closed1971
Websiteassa.saao.ac.za/sections/history/observatories/rep_obs/
Location of Union Observatory

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.[1] 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).[3]

History

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.[4]:17 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.[4]:17

On 1 April 1903, a new Meteorological Department was temporarily established in Johannesburg.[4]:17 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.[4]:17 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.[4]:18 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.[4]:18 The observatory building was built and the formal opening took place on 17 January 1905 by Governor Milner, but had no astronomical equipment.[4]:19

In 1906 it was lent a Hamberg universal instrument (2 5/8-inch object glass) by Dr Oskar Backlund.[4]:19 In September 1907 a 9-inch Grubb refractor was now used but repolished in 1908.[4]:19 Mr J. Franklin-Adams gifted the observatory a 10-inch triple O.G. Cooke Star-Camera in 1909.[4]:19 J.B. Rissik, Minister for Lands, permitted the purchase of a 26-inch refracting telescope from Sir Howard Grubb in 1909.[4]:19

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.[4]:19 With the removal of the meteorological functions, the observatory was renamed Observatory of the Union of South Africa (Union Observatory) on 1 April 1912.[4]:19 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.[1]

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.[1]

The main-belt asteroid 1585 Union, discovered by Ernest Johnson in 1947, was named for the Union observatory.[5]

Leiden Southern Station

The Leiden Southern Station (081) 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.[7]

Discoveries

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:

715 Transvaalia22 April 1911list [A]
758 Mancunia18 May 1912list [A]
790 Pretoria16 January 1912list [A]
982 Franklina21 May 1922list [A]
1032 Pafuri30 May 1924list [A]
1096 Reunerta21 July 1928list [A]
1116 Catriona5 April 1929list [B]
1132 Hollandia13 September 1929list [C]
1133 Lugduna13 September 1929list [C]
1165 Imprinetta24 April 1930list [C]
1186 Turnera1 August 1929list [B]
1193 Africa24 April 1931list [B]
1194 Aletta13 May 1931list [B]
1195 Orangia24 May 1931list [B]
1196 Sheba21 May 1931list [B]
1197 Rhodesia9 June 1931list [B]
1225 Ariane23 April 1930list [C]
1226 Golia22 April 1930list [C]
1241 Dysona4 March 1932list [A]
1242 Zambesia28 April 1932list [B]
1243 Pamela7 May 1932list [B]
1244 Deira25 May 1932list [B]
1245 Calvinia26 May 1932list [B]
1246 Chaka23 July 1932list [B]
1248 Jugurtha1 September 1932list [B]
1264 Letaba21 April 1933list [B]
1267 Geertruida23 April 1930list [C]
1268 Libya29 April 1930list [B]
1278 Kenya15 June 1933list [B]
1279 Uganda15 June 1933list [B]
1282 Utopia17 August 1933list [B]
1305 Pongola19 July 1928list [A]
1318 Nerina24 March 1934list [B]
1319 Disa19 March 1934list [B]
1320 Impala13 May 1934list [B]
1321 Majuba7 May 1934list [B]
1323 Tugela19 May 1934list [B]
1324 Knysna15 June 1934list [B]
1325 Inanda14 July 1934list [B]
1326 Losaka14 July 1934list [B]
1327 Namaqua7 September 1934list [B]
1336 Zeelandia9 September 1934list [C]
1337 Gerarda9 September 1934list [C]
1342 Brabantia13 February 1935list [C]
1349 Bechuana13 June 1934list [B]
1353 Maartje13 February 1935list [C]
1354 Botha3 April 1935list [B]
1355 Magoeba30 April 1935list [B]
1356 Nyanza3 May 1935list [B]
1357 Khama2 July 1935list [B]
1358 Gaika21 July 1935list [B]
1359 Prieska22 July 1935list [B]
1360 Tarka22 July 1935list [B]
1362 Griqua31 July 1935list [B]
1367 Nongoma3 July 1934list [B]
1368 Numidia30 April 1935list [B]
1383 Limburgia9 September 1934list [C]
1384 Kniertje9 September 1934list [C]
1385 Gelria24 May 1935list [C]
1389 Onnie28 September 1935list [C]
1393 Sofala25 May 1936list [B]
1394 Algoa12 June 1936list [B]
1396 Outeniqua9 August 1936list [B]
1397 Umtata9 August 1936list [B]
1427 Ruvuma16 May 1937list [B]
1428 Mombasa5 July 1937list [B]
1429 Pemba2 July 1937list [B]
1430 Somalia5 July 1937list [B]
1431 Luanda29 July 1937list [B]
1432 Ethiopia1 August 1937list [B]
1456 Saldanha2 July 1937list [B]
1467 Mashona30 July 1938list [B]
1468 Zomba23 July 1938list [B]
1474 Beira20 August 1935list [B]
1490 Limpopo14 June 1936list [B]
1505 Koranna21 April 1939list [B]
1506 Xosa15 May 1939list [B]
1568 Aisleen21 August 1946list [D]
1580 Betulia22 May 1950list [D]
1585 Union7 September 1947list [D]
1595 Tanga19 June 1930list [B][A]
1607 Mavis3 September 1950list [D]
1609 Brenda10 July 1951list [D]
1618 Dawn5 July 1948list [D]
1623 Vivian9 August 1948list [D]
1627 Ivar25 September 1929list [E]
1634 Ndola19 August 1935list [B]
1638 Ruanda3 May 1935list [B]
1641 Tana25 July 1935list [B]
1658 Innes13 July 1953list [F]
1660 Wood7 April 1953list [F]
1663 van den Bos4 August 1926list [A]
1666 van Gent22 July 1930list [C]
1667 Pels16 September 1930list [C]
1670 Minnaert9 September 1934list [C]
1676 Kariba15 June 1939list [B]
1686 De Sitter28 September 1935list [C]
1689 Floris-Jan16 September 1930list [C]
1693 Hertzsprung5 May 1935list [C]
1694 Kaiser29 September 1934list [C]
1701 Okavango6 July 1953list [G]
1702 Kalahari7 July 1924list [E]
1712 Angola28 May 1935list [B]
1731 Smuts9 August 1948list [D]
1738 Oosterhoff16 September 1930list [C]
1752 van Herk22 July 1930list [C]
1753 Mieke10 May 1934list [C]
1760 Sandra10 April 1950list [D]
1784 Benguella30 June 1935list [B]
1816 Liberia29 January 1936list [B]
1817 Katanga20 June 1939list [B]
1819 Laputa9 August 1948list [D]
1879 Broederstroom16 October 1935list [C]
1885 Herero9 August 1948list [D]
1914 Hartbeespoortdam28 September 1930list [C]
1922 Zulu25 April 1949list [D]
1925 Franklin-Adams9 September 1934list [C]
1945 Wesselink22 July 1930list [C]
1946 Walraven8 August 1931list [C]
1948 Kampala3 April 1935list [B]
1949 Messina8 July 1936list [B]
1986 Plaut28 September 1935list [C]
2019 van Albada28 September 1935list [C]
2025 Nortia6 June 1953list [G]
2066 Palala4 June 1934list [B]
2193 Jackson18 May 1926list [A]
2203 van Rhijn28 September 1935list [C]
2378 Pannekoek13 February 1935list [C]
2546 Libitina23 March 1950list [D]
2651 Karen28 August 1949list [D]
2718 Handley30 July 1951list [D]
2801 Huygens28 September 1935list [C]
2825 Crosby19 September 1938list [B]
2829 Bobhope9 August 1948list [D]
2831 Stevin17 September 1930list [C]
2865 Laurel31 July 1935list [B]
2945 Zanstra28 September 1935list [C]
3184 Raab22 August 1949list [D]
3284 Niebuhr13 July 1953list [F]
3300 McGlasson10 July 1928list [A]
3768 Monroe5 September 1937list [B]
4296 van Woerkom28 September 1935list [C]
4359 Berlage28 September 1935list [C]
4511 Rembrandt28 September 1935list [C]
5038 Overbeek31 May 1948list [D]
(5452) 1937 NN5 July 1937list [B]
7102 Neilbone12 July 1936list [B]

References
  1. "Republic Observatory (known as Johannesburg or Union Observatory)". Astronomical Society of Southern Africa. 2016. Retrieved 29 December 2016.
  2. "Republic Observatory (known as Johannesburg or Union Observatory)". Astronomical Society of Southern Africa. 2016. Archived from the original on 4 April 2016. Retrieved 29 December 2016.
  3. "Minor Planet Discoverers (Alphabetically)c". Minor Planet Center. 4 September 2016. Retrieved 29 December 2016.
  4. Hers, J. (1987-02-01). "The history of the Transvaal Observatory". Monthly Notes of the Astronomical Society of South Africa. 46 (1–2): 17–19. ISSN 0024-8266.| – via Sabinet (subscription required)
  5. Schmadel, Lutz D. (2007). "(1585) Union". Dictionary of Minor Planet Names – (1585) Union. Springer Berlin Heidelberg. p. 125. doi:10.1007/978-3-540-29925-7_1586. ISBN 978-3-540-00238-3.
  6. "Jan Hers". IAU – International Astronomical Union, individual members. Retrieved 29 December 2016.
  7. "Leiden Southern Station (Hartebeespoort)". Astronomical Society of Southern Africa. 2016. Archived from the original on 27 August 2016. Retrieved 29 December 2016.
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