Robert Stawell Ball

Great Astronomers James Bradley annotated Robert Stawell Ball

James Bradley FRS ( March, 1693 - July 13, 1762 ) was an English astronomer and priest 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, athematical 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. In 1742, Bradley was appointed to succeed Edmond Halley as Astronomer Royal; his reputation enabled him to apply successfully for a set of instruments costing GB£1,000; and with an 8-foot quadrant completed for him in 1750 by John Bird, he accumulated at Greenwich in ten years materials of inestimable value for the reform of astronomy.