Curtiss, Ralph Hamilton

(b. Derby, Connecticut, 8 February 1880; d. Ann Arbor, Milchigan, 25 December 1929)

astronomy.

Curtiss was a skillful and productive spectroscopist who developed experimental techniques and used them to investigate the properties of variable stars.

The youngest of three sons born to Hamilton Burton Curtiss and the former Emily Wheeler, Curtiss grew up in an atmosphere of strict Puritan morality. The family moved in 1892 to California, where he attended high school and the University of California. In the spring of his senior year Curtiss went to Padang, Sumatra, as member of an expedition from Lick Observatory, to observe the solar eclipse of 17–18 May 1901. Returning to Berkeley, he received his B. S. degree in 1901 and his Ph.D. in 1905, while continuing to work at Lick.

In his dissertation (“I. A Method of Measurement and Reduction of Spectrograms for the Determination of Radial Velocities. II. Application to a Study of the Variable Star W Sagittarii”) Curtiss described a way to get more precise line-of-sight velocities from the Doppler shifts observed in stellar spectra and made the first of his many contributions to the subject of Cepheid variable stars.

During two years at the Allegheny Observatory of the University of Pittsburgh (then called the Western University of Pennsylvania), Curtiss designed his first stellar spectrograph and discovered with it a third component of the star Algol, thereby confirming a suggestion made by Seth Carlo Chandler in 1888. He went in 1907 to the University of Michigan as an assistant professor. Here he initiated an extensive program of observing close binary stars, Cepheid variables, and stars of high surface temperature with bright line spectra (“Class B emission” stars). He became professor in 1918 and married Mary Louise Walton in 1920. Following the death of William Joseph Hussey, he was named director of the Detroit observatory of the University of Michigan in 1927; Heber Doust Curtis succeeded him in that post when he died two years later.

Curtisss was elected fellow of the Royal Astronomical Society of London in 1927. He also served as councilor of the American Astronomical Society and as a member ofCommission 29 of the International Astronomical Union.

BIBLIOGRAPHY

I Original Works. Curtiss’ dissertation, “I. A Method of Measurement and Reduction of Spectrograms for the Determination of Radial Velocities. II. Application to a Study of the Variable Star W Sagittarii,” was published in Astrophsial Journal, 20 (1904), 149–187; and in Bulletin of the Lick Observatory, 3 (1904), 19–40. His work on Algol was “On the Orbital Elements of Algol,” in Astrophysical journal, 28 (1908), 150–161; and “The Orbit of Algol from Observations Made in 1906 and 1907” (dated 24 March 1908), in Publications of the Allegheny Observatory of the University of Pittsburgh, 1 (1910), 25–32, written with Frank Schlesinger.

What probably constitutes Curtiss’ major contribution to astronomy appeared in six memoirs on the ClassB emission stars; “The Photographic Spectrum of β Lyrae,” in Publications of the Allegheny Observatory of the University of Pittsburgh, 2 (1912), 73–120; “The Spectrum of γ Cassiopeiae,” in Publications of the Astronomical Observatory of the University of Michigan, 2 (1916), 1–35; “Changes in the Spectrum f¹ Cygni,” ibid., 36–38; “Changes in the Spectrum of H. R. 985,” ibid., 39–44; “Widths of Hydrogen and Metallic Emission Lines in Class B Stellar Spectra,” ibid., 3 (1923), 1–15; and “A Pictorial Study of the Spectrum of Nova Geminorum II,” ibid., 253–255, with pls. E–K.

The list of Curtiss’ publications in Poggendorff, V (1926), 255, and VI, pt. I (1936), 502–503, appears to be complete through 1931—although for articles in vol. 3 of Publications of the Observatory of the University of Michigan (also known at that time as Detroit observatory) appear twice (once under each heading). Missing are four posthumous works; Curtiss’ excellent historical summary, “Classification and Description of Stellar Spectra,” which appeared (in English) as ch. I of Handhuch der Astrophysik, V, pt. I (Berlin, 1932); and three articles prepared for publication by Dean Benjamin McLaughlin: “The Light Curve of R Scuti, 1911–1931,” in publications of the Observatory of the University of Michigan, 4 (1932), 129–133; “Variations of Emission Lines in Three B Spectra,” ibid., 4 (1932), 163–174; and “Visual Light Curves of Beta Lyrae,” ibid., 5(1934), 177–184. The material on novae mentioned in Rufus’ obituary of Curtiss (see below) does not seem to have been published.

II. Secondary Literature. The facts of Curtiss’ life can be found in several brief obituary notices: two by Edward Arthur Milbe, in Observatory, notices: two by Edward Arthus Milne, in Observatory, 53 (1930), 54–56, and Monthly Notices of the Royal Astronomical Society, 90 (1930), 362–363; and two by Joseph Haines Moore, in Science, n.s.72 (1930), 58–60, and Publications of the Astronomical Society of the Pacific, 42 (1930), 37–40. The latter includes a portrait, as do two obituaries written by Curtiss’ students: Dean Benjamin McLaughlin, in Journal of the Royal Astronomical Society of Canada. 24 (1930), 153–158; and Will Carl Rufus, in Popular Astronomy, 38 (1930), 190–199.

Sally H. Dieke