James Bradley was born in March 1693, in Sherborne, Gloucestershire, England. He was educated at Oxford and earned a master's degree in 1717. He had great aptitude in mathematics and was befriended by Isaac Newton and Edmond Halley. Since he felt he could not make a living in astronomy, he became a vicar in the Church of England, but gave that up in 1721 and returned to Oxford to teach.

Bradley's great goal in life was to measure the parallax of the stars--a measurable shift in the apparent position of an object resulting from the Earth's orbit around the Sun. When Nicholas Copernicus claimed the Earth was in motion around the Sun, it seemed obvious that parallax, due to the movement of the Earth, should be seen; it was not. While Copernicus contended that this was due to the great distance of the stars, his critics charged it was because the...