James Bradley FRS (March 1693 – 13 July 1762) was an English
astronomer and served as
Astronomer Royal from 1742, succeeding
Edmond Halley. He is best known for two fundamental discoveries in astronomy, the
aberration of light (1725–1728), and the
nutation of the Earth's axis (1728–1748). These discoveries were called "the most brilliant and useful of the century" by
Jean Baptiste Joseph Delambre, historian of astronomy, mathematical astronomer and director of the Paris Observatory, in his history of astronomy in the 18th century (1821), because "It is to these two discoveries by Bradley that we owe the exactness of modern astronomy. .... This double service assures to their discoverer the most distinguished place (after
Hipparchus and
Kepler) above the greatest astronomers of all ages and all countries."