N. R. Pogson
|Norman Robert Pogson|
23 March 1829|
|Died||23 June 1891
|Asteroids discovered: 8|
|42 Isis||23 May 1856|
|43 Ariadne||15 April 1857|
|46 Hestia||16 August 1857|
|67 Asia||17 April 1861|
|80 Sappho||2 May 1864|
|87 Sylvia||16 May 1866|
|107 Camilla||17 November 1868|
|245 Vera||6 February 1885|
Youth and Education
He was the son of George Owen Pogson, a hosiery manufacturer, lace dealer and commission agent, "with enough income to support an extended family" (Reddy et al.), and his wife, Mary Ann.
It was intended that he should follow his father into business, and he was accordingly sent for 'commercial education', but he was fascinated by science, and his mother supported and encouraged this interest. He left school at 16, intending to teach mathematics. However, in 1846 he commenced training in astronomy at the South Villa Observatory in Regents Park in London. By the time he was 18 years old, he had computed the orbital elements of two comets.
In 1860 he travelled to Madras, India, becoming the government astronomer. At the Madras Observatory he produced the Madras Catalogue of 11,015 stars. He also discovered eight asteroids and six variable stars.
His most notable contribution was to note that in the stellar magnitude system introduced by the Greek astronomer Hipparchus, stars of the first magnitude were a hundred times as bright as stars of the sixth magnitude. Pogson's suggestion in 1856 was to make this a standard; thus, a first magnitude star is 1001/5 or about 2.512 times as bright as a second magnitude star. This fifth root of 100 is known as Pogson's Ratio.
The magnitude relation is given as follows:
- m1 - m2 = -2.5 log10 (L1 / L2)
where m is the stellar magnitude and L is the luminosity, for stars 1 and 2.
During his career he discovered a total of eight asteroids and 21 variable stars. He headed the Madras Observatory for 30 years until his death.
Pogson was married in London in 1849 to Elizabeth Jane Ambrose, by whom he had 11 children. She died on 5 November 1869. He was married again, in Madras on 25 October 1883, to Edith Louisa Stopford Sibley, a widow, aged 33, by whom he had a further three children: Frederick Vere (born in 1885), Edith Vera (born in 1886; died in infancy) and Edith Gladys (born in 1889).
The asteroid Vera, first discovered by Pogson on 6 February 1885, was named at the suggestion of his wife, Edith Pogson.
Pogson's daughter, Elizabeth Isis Pogson (born on 28 September 1852), served as his assistant at the Madras observatory from 1873 - 1881. She went on to become meteorological reporter for Madras. First proposed for a Fellowship of the Royal Astronomical Society in 1886, she was finally admitted to that honour in 1920.
The following celestial features are named after him:
- Asteroid 1830 Pogson.
- The crater Pogson on the Moon.
- Asteroid 42 Isis is believed to be named after his daughter, Elizabeth Isis Pogson
- Reddy, V., Snedegar, K., & Balasubramanian, R. K., 'Scaling the magnitude: the fall and rise of N. R. Pogson' in Journal of the British Astronomical Association (vol.117, no.5) (2007), p.238. National Archives, 1851 England Census (class: HO107; piece: 2228; folio: 267; page 2).
- Reddy et al., loc. cit.
- J.F. Riddick, Who was who in British India (1998), p. 292.
- Marriage registered in Pancras Registration District in the first quarter of 1850. Reddy et al., pp. 242-243. FamilySearch.org, "India, Marriages, 1792-1948"; "India, Births and Baptisms, 1786-1947".
- L.D. Schmadel,Dictionary of Minor Planet Names (sixth edition) (2012), p. 35.
- Principal Probate Registry, Calendar of the Grants of Probate and Letters of Administration made in the Probate Registries of the High Court of Justice in England (1947), p. 473.
- Hockey, T. (editor-in-chief), Biographical Encyclopedia of Astronomers (vol. II, M-Z) (2007), p. 920. FamilySearch.org, "England Births and Christenings, 1538-1975".
- Reddy et al., p. 243.
- 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
- A link on his works: http://adszip.cfa.harvard.edu/ui/abs/1968ASPL...10..145J/similar
- Norman Robert Pogson - Irineu Gomes Varella (Portuguese)