born June 19, 1902, Pittsburgh, Pa., U.S.
died Aug. 24, 1971, Englewood, N.J.
U.S. astronomer.
He received his Ph.D. from Yale University. He was one of the first to apply IBM punched-card equipment to the reduction of astronomical data and to describe planetary orbits numerically. As director of Columbia University's Watson Scientific Computing Laboratory from 1945, he used computers to determine precise planetary positions and made major contributions to the study of the orbit of the Moon, one of whose craters is named for him.