James Challis (December 12, 1803 – December 3, 1882) was a British clergyman and astronomer. He was born in Braintree, Essex and died in Cambridge.

Challis became director of the Cambridge Observatory in 1836 and it was 1846 when John Herschel finally persuaded him to join in the search for an eighth planet in the solar system. Cambridge mathematician John Couch Adams had predicted the location of such a planet as early as 1843, based on irregularities in the orbit of Uranus. Adams failed to promote his prediction successfully and there was little enthusiasm for a systematic search of the heavens until Herschel's intervention. Challis finally began his, somewhat reluctant, search in July 1846, unaware that Frenchman Urbain Le Verrier had independently made an identical prediction. German astronomer Johann Gottfried Galle finally confirmed Le Verrier's prediction on September 23. The planet was named Neptune. It soon became apparent from Challis's notebooks that he had observed Neptune twice, a month earlier, failing to make the identification through lack of dilligence.

The distributed.net UK team originally Cambridge University and CIX based is named "Prof. James Challis Most Excellent UK Team" in his honour.

External link

• Obituary (http://cdsads.u-strasbg.fr//full/seri/MNRAS/0043//0000160.000.html)

Bibliography

• Standage, T (2000) The Neptune File: Planet Detectives and the Discovery of Worlds Unseen ISBN 071399472X