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First Cambridge Catalogue Of Radio Sources
The First Cambridge Catalogue of Radio Sources (1C) refers to the catalogue listed in the article ''Ryle M, Smith F G & Elsmore B (1950) MNRAS vol 110 pp508-523 "A Preliminary Survey of Radio Stars in the Northern Hemisphere"'' The 1C catalogue listed about 50 radio sources, detected at 3.7 m with a fixed meridian interferometer. According to researchers at the Special Astrophysical Observator most of the sources from 1C were later recognized to be the effect of confusion, i.e. they were not real objects. The survey was produced using the Long Michelson Interferometer at the Old Rifle Range in Cambridge in 1950. This device operated primarily at a wavelength of 3.7 metres, with an aperture of 110λ, and was operated using Ryle's phase switching technique. Francis Graham-Smith Sir Francis Graham-Smith (born 25 April 1923) is a British astronomer. He was the thirteenth Astronomer Royal from 1982 to 1990 and was knighted in 1986. Biography Education He was educated at Rossall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting original research in relevant fields. Despite the name, the journal is no longer monthly, nor does it carry the notices of the Royal Astronomical Society. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second volume, after the Astronomical Society of London became the Royal Astronomical Society (RAS). Until 1960 it carried the monthly notices of the RAS, at which time these were transferred to the newly established ''Quarterly Journal of the Royal Astronomical Society'' (1960–1996) and then to its successor journal ''Astronomy & Geophysics'' (since 1997). Until 1965, MNRAS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Michelson Interferometer
The Long Michelson Interferometer was a radio telescope interferometer built by Martin Ryle and co-workers in the late 1940s beside a rifle range to the west of Cambridge, England. The interferometer consisted of 2 fixed elements 440m apart to survey the sky using Earth rotation. It produced thPreliminary survey of the radio stars in the Northern Hemisphereat 45 MHz - 214 MHz. The telescope was operated by the Radio Astronomy Group of Cambridge University. Martin Ryle and Antony Hewish received the Nobel Prize for Physics in 1974 for this and later work in radio interferometry. ReferencesA preliminary survey of the radio stars in the Northern Hemisphere Ryle, M.; Smith, F. G.; Elsmore, B., (1950), Monthly Notices of the Royal Astronomical Society ''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge
Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge became an important trading centre during the Roman and Viking ages, and there is archaeological evidence of settlement in the area as early as the Bronze Age. The first town charters were granted in the 12th century, although modern city status was not officially conferred until 1951. The city is most famous as the home of the University of Cambridge, which was founded in 1209 and consistently ranks among the best universities in the world. The buildings of the university include King's College Chapel, Cavendish Laboratory, and the Cambridge University Library, one of the largest legal deposit libraries in the world. The city's skyline is dominated by several college buildings, along with the spire of the Our Lady and the English Martyrs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martin Ryle
Sir Martin Ryle (27 September 1918 – 14 October 1984) was an English radio astronomer who developed revolutionary radio telescope systems (see e.g. aperture synthesis) and used them for accurate location and imaging of weak radio sources. In 1946 Ryle and Derek Vonberg were the first people to publish interferometric astronomical measurements at radio wavelengths. With improved equipment, Ryle observed the most distant known galaxies in the universe at that time. He was the first Professor of Radio Astronomy in the University of Cambridge and founding director of the Mullard Radio Astronomy Observatory. He was the twelfth Astronomer Royal from 1972 to 1982. Ryle and Antony Hewish shared the Nobel Prize for Physics in 1974, the first Nobel prize awarded in recognition of astronomical research. In the 1970s, Ryle turned the greater part of his attention from astronomy to social and political issues which he considered to be more urgent. Education and early life Martin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Switching
A phase switch is a device used to increase the discrimination and sensitivity of an interferometer, especially at radio frequencies; an extra half-wave path difference is switched in, at well defined frequency, between the two interfering signal sources. In-phase signals then become out of phase and vice versa, so that the signal output becomes modulated by the switching frequency, and can be more easily filtered from the internally generated noise. (The discrimination is highest for sources which are small compared with the interferometer-fringe spacing) Its use in radio astronomy is generally credited to Martin Ryle Sir Martin Ryle (27 September 1918 – 14 October 1984) was an English radio astronomer who developed revolutionary radio telescope systems (see e.g. aperture synthesis) and used them for accurate location and imaging of weak radio source ..., and used extensively in the 1C radio survey. Interferometry {{physics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis Graham-Smith
Sir Francis Graham-Smith (born 25 April 1923) is a British astronomer. He was the thirteenth Astronomer Royal from 1982 to 1990 and was knighted in 1986. Biography Education He was educated at Rossall School, Lancashire, England, and attended Downing College, Cambridge from 1941. Career In the late 1940s he worked at the University of Cambridge on the Long Michelson Interferometer. In 1964 he was appointed Professor of Radio Astronomy the University of Manchester and in 1981 director of the Nuffield Radio Astronomy Laboratories, part of the University of Manchester at Jodrell Bank. He was also Director of the Royal Greenwich Observatory from 1975 to 1981. He appeared in Episode 13 of Series 4 of Treasure Hunt when the show visited Jodrell Bank, giving presenter Anneka Rice a piggy back to allow her to reach a clue. Bibliography * ''Optics'' (1971) * ''Pathways to the Universe'' (1988) * ''Pulsar Astronomy'' (1990) * ''An Introduction to Radio Astronomy'' (1997) * ''Unsee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 81
Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major. It has a D25 isophotal diameter of . Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus (which harbors a 70 million supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers. In late February 2022, astronomers reported that M81 may be the source of FRB 20200120E, a repeating fast radio burst. Discovery Messier 81 was first discovered by Johann Elert Bode on 31 December 1774. Thus, it is sometimes referred to as "Bode's Galaxy". In 1779, Pierre Méchain and Charles Messier reidentified Bode's object, hence listed it in the Messier Catalogue. Visibility The galaxy is to be found approximately 10° northwest of Alpha Ursae M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
