James Bradley (1693-1762), English astronomer. Bradley was born at Sherborne in Gloucestershire and was educated at Balliol College, Oxford. He studied theology and took holy orders in 1719. However, while at university he had been tutored in astronomy by his uncle and in 1721 he resigned his church position to take the Savillian chair of astronomy at Oxford. Bradley was a brilliant observer. While observing the parallax of the star Gamma Draconis he noticed the cyclical motion he expected was out of phase with the Earth's annual orbit. He showed that this could be explained by a combination of a finite speed of light and the speed of the Earth's orbit. This effect is known as the aberration of light. He also discovered nutation, a precession of the Earth's axis of rotation due to tidal effects. In 1742 Bradley succeeded Halley as Astronomer Royal.