Horace Welcome Babcock was an American astronomer. He was the son of Harold D. Babcock.
He invented and built a number of astronomical instruments, and in 1953 was the first to propose the idea of adaptive optics. He specialized in spectroscopy and the study of magnetic fields of stars. He proposed the Babcock Model, a theory for the magnetism of sunspots.
During World War II, he was engaged in radiation work at MIT and Caltech. After the war he began a productive collaboration with his father. His undergraduate studies was at Caltech and his doctorate from University of California, Berkeley.
Babcock's doctoral thesis contained one of the earliest indications of dark matter. He reported measurements of the rotation curve for Andromeda which suggested that the mass-to-luminosity ratio increases radially. He, however, attributed it to either absorption of light within the galaxy or modified dynamics in the outer portions of the spiral and not to any form of missing matter.