A refracting telescope is a type of optical telescope that uses a lens as its objective to form an image. The refracting telescope design was originally used in spyglasses and astronomical telescopes but is also used for long-focus camera lenses. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes, the refracting telescope has been superseded by the reflecting telescope, which allows larger apertures. A refractor's magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece.
Boyden Observatory is an astronomical research observatory and science education centre located in Maselspoort, 20 kilometres (12 mi) north-east of the city of Bloemfontein in Free State, South Africa. The observatory is managed by the Physics Department of the University of the Free State (UFS). The Friends of Boyden assist the observatory as a public support group, organising open evenings and protecting its public interest. Boyden also makes use of members of ASSA Bloemfontein Centre, the amateur astronomy club of the city, for presenters and telescope assistants.
Sir James South FRS FRSE PRAS FLS LLD was a British astronomer.
Franz Friedrich Ernst Brünnow was a German astronomer.
Armagh Observatory is an astronomical research institute in Armagh, Northern Ireland. Around 25 astronomers are based at the observatory, studying stellar astrophysics, the Sun, Solar System astronomy and Earth's climate.
Dunsink is a townland in the civil parish of Castleknock, Dublin, in Ireland. The townland has an area of approximately 1.7 square kilometres (0.66 sq mi), and had a population of 323 people as of the 2011 census.
A. David Andrews is an Irish astronomer. He studied at Oriel College Oxford and University of Dublin. He spent the early 1960s in Denmark working with astrophysicist M. Rudkjobing at the Aarhus Observatory. He moved on in 1963 to Armagh Observatory in Northern Ireland where he spent the next 35 years. Andrews discovered the minor planet 1727 Mette whilst at the Boyden Observatory located in Bloemfontein, South Africa, where he was acting director. It was while at Boyden Observatory that he commenced his lifelong work on flare stars. He was the first to make full use of computers, in 1968, at Armagh Observatory. Andrews was Editor of the Irish Astronomical Journal following Ernst Öpik, and in 1967 became a founder member of Commission 27 Working Group on Flare Stars of the International Astronomical Union.
Markree Observatory was an astronomical observatory in County Sligo, Ireland. The asteroid 9 Metis was discovered from this observatory in 1848 by Cooper's assistant Andrew Graham using a comet seeker telescope. The observatory was also home to the largest refractor of the early 1830s, which had a 13.3-inch (340 mm) aperture Cauchoix of Paris lens; the largest in the world at that time. The observatory also housed a number of instruments and was operated to varying degrees throughout the 19th century.
Grubb Parsons was a historic manufacturer of telescopes, active in the 19th and 20th centuries. They built numerous large research telescopes, including several that were the largest in the world of their type.
Thomas Grubb was an Irish optician and founder of the Grubb Telescope Company.
Reverend William Frederick Archdall Ellison FRAS(28 April 1864 – 31 December 1936) was an Irish clergyman, Hebrew scholar, organist, avid amateur telescope maker, and, from 1918 to 1936, director of Armagh Observatory in Armagh, Northern Ireland. He was the father of Mervyn A. Ellison, the senior professor of the School of Cosmic Physics at Dunsink Observatory from 1958 to 1963.
Great refractor refers to a large telescope with a lens, usually the largest refractor at an observatory with an equatorial mount. The preeminence and success of this style in observational astronomy defines an era in modern telescopy in the 19th and early 20th century. Great refractors were large refracting telescopes using achromatic lenses. They were often the largest in the world, or largest in a region. Despite typical designs having smaller apertures than reflectors, great refractors offered a number of advantages and were popular for astronomy. It was also popular to exhibit large refractors at international exhibits, and examples of this include the Trophy Telescope at the 1851 Great Exhibition, and the Yerkes Great Refractor at the 1893 World's Fair in Chicago.
The Andrews Professor of Astronomy is a chair in astronomy in Trinity College Dublin, that was established in 1783 in conjunction with the establishment of Dunsink Observatory.
Robert-Aglaé Cauchoix was a French optician and instrument maker, whose lenses played a part in the race of the great refractor telescopes in the first half of the 19th century.
Edward Joshua Cooper was an Irish landowner, politician and astronomer from Markree Castle in County Sligo. He sat in the House of Commons of the United Kingdom from 1830 to 1841 and from 1857 to 1859, but is best known for his astronomy, and as the creator of Markree Observatory.
Henry Ussher (1741–1790) was an Irish mathematician and astronomer, best known as the inaugural Andrews Professor of Astronomy at Trinity College Dublin (TCD), a title later accompanied with the designation Royal Astronomer of Ireland. Ussher was a key player in the setting up of Dunsink Observatory outside the city of Dublin, and was its first director.
James Archibald Hamilton (1748–1815) FRIA, Irish cleric and astronomer, was born in the area of Athlone, Co. Westmeath, Ireland.
The Sheepshanks Equatorial Telescope was a 6.7-inch (170 mm) aperture refracting telescope installed in 1838 at the Royal Observatory in Greenwich. The telescope was donated to the observatory by the astronomer Richard Sheepshanks. The telescope had a doublet objective lens made by Cauchoix of Paris. Originally it was mounted on a clockwork driven equatorial mounting by the Grubb Telescope Company on a stone pillar.
Patrick Wayman was an English astronomer and director of Dunsink Observatory from 1964 to 1992.
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