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29-458: The observatory was initially located on the university building in the centre of Leiden before a new observatory building and dome were constructed in the university's botanical garden in 1860. It remained there until 1974 when the department moved to the science campus north-west of the city. Notable astronomers that have worked or directed the observatory include Willem de Sitter , Ejnar Hertzsprung and Jan Oort . Leiden University established

58-533: 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

87-618: 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

116-466: A new observatory. From 1859 to 1909 the Netherlands civil time was set according to the local civil time at the observatory; communicated using the telegraphic network. By 1860 the new observatory building was completed. The new building was constructed in a quiet side of the city inside the university's botanical gardens. It consisted of a number of offices, living quarters for astronomers, and

145-433: A number of new instruments including new telescopes and tools, before his death in 1742. Gravesande's successor was Johan Lulofs who used the observatory to observe Halley's comet in 1759 and solar transits of Mercury (in 1743 and 1753) and Venus (in 1761). In November 1768 when Lulofs died, Dionysius van de Wijnpersse took over responsibility for the observatory until Pieter Nieuwland became its director in 1793 for

174-468: A number of observing domes containing telescopes. In 1873 two new rooms were added to the building in order to house the tools required to verify nautical instruments; tools used to test compasses, sextants and other instruments. Two of the domes were rebuilt, one in 1875 and the other in 1889. More new buildings were constructed before the end of the 19th century including the Western tower in 1878, one to

203-506: A short segment on the Dutch astronomy program Heel Nederland Kijkt Sterren . During this segment the science populariser Govert Schilling and the science historian David Baneke talked about its origins. Einstein is noted for his visits to Leiden Observatory during World War I. The old Observatory building facilities (from 1860s) was restored in the 2010s. While not longer the base for the modern Leiden Observatory academically, it does have

232-421: A year until he died in 1794. For a number of years the curators attempted to find a suitable astronomer to look after the observatory, eventually employing Jan Frederik van Beeck Calkoen in 1799, who left in 1805. In 1817 the observatory towers were pulled down and rebuilt. Frederik Kaiser was appointed lecturer of astronomy and director of the observatory in 1837, and again renovated the observatory, providing

261-421: Is a defunct astronomical observatory in Johannesburg , South Africa that operated from 1903 to 1971. It is located on Observatory Ridge , the city's highest point at 1,808 metres altitude in the suburb 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

290-783: Is no matter and a positive cosmological constant . This results in an exponentially expanding, empty universe. De Sitter was also well-known for his research on the motions of the moons of Jupiter , invited to give the George Darwin Lecture at the Royal Astronomical Society in 1931. Willem de Sitter died after a brief illness in November 1934. In 1912, he became a member of the Royal Netherlands Academy of Arts and Sciences . One of his sons, Ulbo de Sitter (1902 – 1980),

319-494: The East in 1898, and another small building to house a gas engine in the same year (used for electricity until the observatory was connected to the city grid). In 1896 the observatory purchased their first photographic telescope, with a dome being built to house it between then and 1898. In 1923 the observatory formed a research agreement with Union Observatory to allow researchers use of both facilities. The first visitor from Leiden

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348-490: The Leiden Observatory is available at Leiden University Library and digitally accessible through Digital Collections Einstein's Chair is an astronomical observing chair at the Leiden Observatory. This chair, made in 1861, is the only piece of furniture in the observatory that dates from that time. The chair gets its name from the fact that it was used by Albert Einstein on several occasions during his visits to

377-786: 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,

406-567: The astronomical historical items at the facility. Also, a solar telescope was crowd funded to provide live optically transmitted images of the Sun to the Visitor center, which is also known to have offered tours. The archives of the Leiden Observatory and its successive directors, 1829-1992 are held at Leiden University Libraries and are digitally available. Examples: Willem de Sitter Willem de Sitter (6 May 1872 – 20 November 1934)

435-804: 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

464-495: The department still calls itself Leiden Observatory. In much of astronomy, the data came from elsewhere and could be analyzed and studied on the campus; for example in modern times the instruments may even be located in space, with data transmitted back to Earth and then studied on a computer display. (An example of this was the Astronomical Netherlands Satellite , launched in 1974.) The archive of

493-660: 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,

522-519: The observatory in 1633; astronomy had been on the curriculum for a long time, and due to possession of a large quadrant built by Rudolph Snellius , Jacobus Golius requested an observatory in which to use it. The observatory was one of the first purpose-built observatories in Europe . Though Golius used the observatory regularly, no publications came from its use by him. It is not known whether Golius had any instrumentation other than Snellius' quadrant at

551-482: The observatory owned two other quadrants, a 12-inch telescope, two objectives , and several smaller telescopes. For the next two years, Lotharius Zumbach de Coesfeld ran the observatory until his appointment as professor of mathematics in Kassel in 1708. Between then and 1717 the observatory went without a director until Willem 's Gravesande was appointed director. During his time at the observatory, Gravesande purchased

580-410: 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 ) . The origins of

609-437: The observatory. In 1682 Burchardus de Volder became professor of mathematics at the university and thus took over responsibility for the observatory. During his tenure, the observatory was enlarged, including a second turret to house a brass sextant which he purchased, and the rebuilding of the old turret. Both turrets had rotating roofs. Upon retiring in 1705, de Volder handed over a catalogue of instruments which showed that

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638-450: The observatory. Einstein was a frequent visitor of the building during his professorship at Leiden university due to his good friendship with the director, Willem de Sitter . The chair can be found in the largest dome of the observatory, the so-called 10-inch dome (named after the 10-inch telescope that is placed inside). The chair is still used by observers and a popular attraction at the observatory. On 21 October 2015, Einstein's Chair got

667-399: The towers with rotatable roofs with full shutters, and reinforcing the north-western tower. Kaiser also acquired a number of new instruments and telescopes with which he made observations including that of comets, planets, and binary stars . As a result of the increased interest in astronomy brought about due to Kaiser's popular writings and teachings, a commission was founded in 1853 to fund

696-442: Was Ejnar Hertzsprung . In 1954 the telescopes were moved to Hartbeespoort . The collaboration lasted until 1972. The old Observatory building of this period was restored from 2008 to 2012, and in the 2010s houses a visitor center and also has tours. The astronomy department moved to the science campus north-west of the city centre in 1974. Although professional astronomical observations are no longer carried out from Leiden itself,

725-718: Was a Dutch mathematician , physicist , and astronomer . The De Sitter universe is a cosmological model named after him. Born in Sneek , De Sitter studied mathematics at the University of Groningen and then joined the Groningen astronomical laboratory. He worked at the Cape Observatory in South Africa (1897–1899). Then, in 1908, De Sitter was appointed to the chair of astronomy at Leiden University . He

754-726: Was a Dutch geologist, and one of Ulbo's sons was a Dutch sociologist Ulbo de Sitter (1930 – 2010). Another son of Willem, Aernout de Sitter (1905 – 15 September 1944 ), was the director of the Bosscha Observatory in Lembang , Indonesia (then the Dutch East Indies), where he studied the Messier 4 globular cluster . Union Observatory Union Observatory , also known as Transvaal Observatory , Republic Observatory and Johannesburg Observatory ( 078 ),

783-563: Was director of the Leiden Observatory from 1919 until his death. De Sitter made major contributions to the field of physical cosmology . He co-authored a paper with Albert Einstein in 1932 in which they discussed the implications of cosmological data for the curvature of the universe. He also came up with the concept of the De Sitter space and De Sitter universe , a solution for Einstein's general relativity in which there

812-553: 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

841-625: Was named for the Union observatory. Union Observatory went through a number of name changes: Its directors were: 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. The Minor Planet Center credits Union Observatory ("Johannesburg"), as

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