Edmond Halley (1656-1742), English astronomer. Halley deduced that the comets seen in 1456, 1531, 1607 and 1682 were the same object (Halley's Comet), successfully predicting its return in 1758. In 1718 he observed the proper motion of the stars. He devised the first diving bell, mapped the Earth's winds, constructed mortality tables, and linked the aurora borealis with the Earth's magnetic field. He was Astronomer Royal from 1720 to 1742.