Born Oct. 25, 1877, in Oyster Bay, New York; died Feb. 18, 1957, in Princeton. American astronomer.

Russell graduated in 1900 from Princeton University, where he was a professor in the period 1911–47. From 1912 to 1947 he was director of the astronomical observatory at Princeton University. Russell was the author of works on astrophysics, stellar astronomy, and cosmogony. His most important works dealt with the classification of stars, the determination of stellar masses and stellar parallaxes, the calculation of the orbits of binary stars, in particular eclipsing variable stars, the application of ionization theory to astronomical phenomena, and the determination of the brightness and albedo of the planets. Russell established the relationship between the luminosity of stars and their spectral class. He originated one of the first hypotheses regarding stellar evolution.