Olin Chaddock Wilson, Jr. (1909-1994) joined the Mount Wilson Observatory in 1931 as a research assistant and in 1936 became a staff member. Wilson was educated as an undergraduate at the University of California and in 1934 received the first Ph. D. in Astronomy awarded by the California Institute of Technology. Wilson's professional work was devoted to various phases of spectroscopy, including the stellar radial velocity program, various investigations of stellar atmospheres and interstellar material, Wolf-Rayet stars, planetary nebulae, and stellar chromospheres. By intensive analysis of the H and K lines of ionized calcium he showed that other stars besides the sun have cycles of activity. With M.K. Vainu Bappu, he found a means of determining luminosity, and thus distance, of stars from the widths of these two lines. Wilson started the HK Project, which continues to use Mt. Wilson telescopes to monitor a number of nearby stars in search of starspot cycles. He also investigated spectra of nebulae and eclipsing stars. He retired in 1974, and in 1984 he was awarded the Bruce Medal, an award for lifetime achievement in astronomy given by the Astronomical Society of the Pacific.
From the description of Papers of Olin C. Wilson, 1930-1990. (Huntington Library, Art Collections & Botanical Gardens). WorldCat record id: 122499759
From the description of Oral history interview with Olin C. Wilson, 1978 July 11. (Unknown). WorldCat record id: 78557683