- Norman Robert Pogson
Infobox Scientist
name = Norman Robert Pogson
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caption = Norman Robert Pogson
birth_date =March 23 ,1829
birth_place =Nottingham
death_date =June 23 ,1891
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nationality = English
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field =astronomy
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footnotes =Norman Robert Pogson (born
March 23 ,1829 inNottingham – diedJune 23 ,1891 ) was an Englishastronomer .By the time he was 18 years old, he had computed the orbits of two
comet s. He became an assistant atRadcliffe Observatory inOxford , England in 1851. In 1860 he travelled to Madras,India , becoming the government astronomer. At theMadras Observatory he produced theMadras Catalogue of 11,015stars . He also discovered fiveasteroid s and sixvariable star s.His most notable contribution was to note thatin the
stellar magnitude system introduced by the
Greek astronomerHipparchus , stars ofthe first magnitude were about a hundred times asbright as stars of the sixth magnitude. His suggestionin 1856 was to make this a standard, so each decrease in magnitude represented a decrease in brightness equal to the fifth-root of 100 (or about 2.512). The "Pogson Ratio " became the standard method of assigning magnitudes.The magnitude relation is given as follows:
:
where "m" is the stellar magnitude and "L" is the
luminosity , for stars "1" and "2".In 1868 and 1871, Pogson joined the Indian solar
eclipse expeditions.During his career he discovered a total of eight asteroids and 21
variable star s. He headed the Madras Observatory for 30 years until his death.Honours
"The following celestial features are named after him:"
*Asteroid 1830 Pogson .
* Pogson crater on theMoon .References
* [http://articles.adsabs.harvard.edu//full/seri/MNRAS/0017//0000012.000.html Magnitudes of Thirty-six of the Minor Planets for the first day of each month of the year 1857] , N. Pogson, MNRAS 17 pp 12 1856 in which Pogson first introduced his magnitude system
External links
* [http://www.uranometrianova.pro.br/historia/hda/0002/pogson.htm Norman Robert Pogson - Irineu Gomes Varella] (Portuguese)
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