2010 November 17 13:04 SAST

Deep sky birthdays for November

Three deep sky observers of yore have birthdays this week: William Herschel (1738), the Fourth Earl of Rosse, and Stephane Javelle.

Friedrich Wilhelm (William) Herschel was born on 15 November 1738 in Hanover, Germany.

"As the discoverer of the planet Uranus and the most successful practitioner of the new field of stellar astronomy, Sir William Herschel expanded the scope of the known Solar System and of the Universe beyond it."

"Some of Herschel’s most innovative research regarded the 'nebulae' – a general term at that time for what are today recognized as reflection nebulae, HII regions, planetary nebulae, open and globular clusters, and galaxies. Although only a hundred such objects were known when Herschel began to observe them, he discovered and cataloged over 2,400 more and brought them to a central position in his cosmology."

"Although Herschel had by 1811 backed away from his earlier (and correct) belief that some nebulous objects are island universes independent of the Milky Way, his exhaustive observations, extensive catalogs, and careful speculations regarding the stars and nebulae were enough to lay firm foundations for cosmology and stellar astronomy. The latter field, although it scarcely existed before Herschel made it central to his research, eventually emerged as the dominant discipline of modern astronomy."

[Crowe, M.J. and Lafortune, K.R., in Hockey (2007)]

Herschel died on 25 August 1822 in Slough, England.

Laurence Parsons was born on 17 November 1840 at Birr Castle (King's County, Ireland).

He was the eldest son of William Parsons, the Third Earl of Rosse, and shared his father’s enthusiasm for astronomy, continuing the study of nebulae and star clusters at Birr Castle.

He also carried out groundbreaking work on the infrared emission of the Moon, and even succeeded in making an excellent estimate of its surface temperature.

Known in his youth as Lord Oxmantown he studied maths and physics at Trinity College, Dublin, and graduated in 1864.

After completing his studies he turned to the eyepiece and started to observe and sketch nebulae with the 3-foot and 6-foot reflectors, from time to time accompanied by Robert Ball.

His first scientific publication (in 1866) dealt with a water clock to drive an equatorial telescope mounting.

This was followed by a review article of all observations made of the Orion Nebula at Birr Castle since 1849. The article included an engraving of the nebula that John Dreyer said was "always of value as a faithful representation of the appearance of the Orion nebula in the largest telescope of the nineteenth century."

The Third Earl died in October 1867, and Parsons succeeded to the title and the estates.

In 1868, the Fourth Earl began his work on the study of radiant heat from the Moon.

He was elected chancellor of the University of Dublin in 1885 and remained in office until his death, at Birr Castle, on 29 August 1908.

Stephane Javelle was born on 16 November 1864 in Lyon, France.

In 1884 he was appointed "student astronomer" at Nice Observatory, and by 1889 he was using the 76cm refractor at Mont-Gros, the largest refractor in the world at the time.

After a period doing comet and asteroid work, he began (in 1890) to focus on searching for faint nebulae.

His first catalogue of deep sky objects was published in 1895, a second in 1897, and a third in 1908. His fourth and final list (printed only as a preliminary monograph) appeared in 1912.

Overall, in 20 years of uninterrupted systematic search for nebulae, he had discovered and measured 1869 objects. Over half of the objects listed in the Index Catalogue (Dreyer 1895) were credited to Javelle, and 17% of the discoveries included in the Second Index Catalogue were his.

In 1899 ownership of Nice Observatory was transferred to La Sorbonne, Paris, and Javelle was assigned other tasks that left him little time to continue his search for nebulae.

Javelle died on August 3, 1917, in Nice, France.

A photo of Javelle appears on Wolfgang Steinicke's "Javelle" web page.

For further details, see "Biographical Encyclopedia of Astronomers", edited by Thomas Hockey (Springer 2007)

Bio.Encyc.Astronomers (2007) Hockey, T. (ed) Springer.