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Babcock, Horace Welcome

Born Pasadena, California, USA, 13 September 1912

Died Santa Barbara, California, USA, 29 August 2003

Horace Babcock was the son of Harold Babcock ; the two shared many scientific interests, collaborated on some important studies of the Sun and instrument design, and received several of the same honors (though never together).

Horace Babcock was born in Pasadena, where his father was on the staff of the Mount Wilson Observatory (1908-1948). Babcock attended Caltech as an undergraduate, completing his B.S. in physics in 1934. He obtained a Ph.D. in astronomy from the University of California at Berkeley in 1938, studying the dynamics of M31 using Lick long‐slit spectra. His thesis established the trailing nature of the spiral pattern and considerably extended the earlier studies of Vesto Slipher , Frances Pease , and Ernst Öpik .

Babcock's spectra showed a large rotation speed for M31 very far from its center, implying a mass and mass‐to‐luminosity ratio