The English astronomer James Bradley (1693-1762), one of the most determined and meticulous astronomers, discovered the aberration of light and the nutation of the earth's axis.

James Bradley, who was the nephew of the astronomer James Pound, was born at Sherborne, Gloucestershire, in March 1693. He studied at Balliol College, Oxford, and took orders in 1719, when he was given his living at Bridstow. In the meantime he had become a skilled astronomer in the techniques of the day, under the instruction of his uncle. In 1718 he was elected a fellow of the Royal Society, and at the early age of 28 he became Savilian professor of astronomy at Oxford and so resigned from Bridstow.

Bradley lived at a time when an astronomer had to be his own technician--repairing, maintaining, and even making his own equipment. High magnifications were obtained by telescopes with lenses of great focal length, often so long...