Ralph Hamilton Curtiss (8 February 1880 – 25 December 1929) was an American astronomer and a professor of astrophysics at the

University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...

. His main work was on stellar spectra and the identification of spectral

binaries A binary file is a computer file that is not a text file. The term "binary file" is often used as a term meaning "non-text file". Many binary file formats contain parts that can be interpreted as text; for example, some computer document file ...

as well as quantitative studies based on the stellar spectra to study their atmospheres. Curtiss was born in Derby, Connecticut where his parents Hamilton Burton and Emily Wheeler were Puritans. He was the youngest of three sons, a brother being

David Raymond Curtiss David Raymond Curtiss (January 12, 1878 – April 29, 1953) was an American mathematician. He served as president of the Mathematical Association of America from 1935 to 1936. He was also vice president of the American Mathematical Society and th ...

. The children grew up in Redlands, California after the family moved there in 1892 and Ralph entered the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Francisco, ...

in 1897. He was inspired into physics by E.P. Lewis and into astronomy by

A. O. Leuschner Armin Otto Leuschner (January 16, 1868 – April 22, 1953) was an American astronomer and educator. Biography Leuschner was born on January 16, 1868, in the United States but raised in Germany. He returned to the United States for universi ...

. He became an assistant at the Student's astronomical observatory and in 1901 made a trip as part of the Lick Observatory team to

Padang Padang () is the capital and largest city of the Indonesian province of West Sumatra. With a Census population of 1,015,000 as of 2022, it is the 16th most populous city in Indonesia and the most populous city on the west coast of Sumatra. Th ...

, Sumatra to observe the solar eclipse of May 18 during which time he received his BS degree in absentia. He then received a

Lick Observatory The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The observatory is managed by th ...

fellowship and continued studies towards his doctorate. He studied the

Cepheid variable A Cepheid variable () is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude. A strong direct relationship between a Cepheid varia ...

W Sagittarii W Sagittarii (W Sgr, Gamma-1 Sagittarii (γ¹ Sgr)) is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star. W Sagittarii is an optical line-of-sight companion nearly a degree from the much bri ...

and examined techniques to determine radial velocity from spectrometric data. His thesis was "''Proposed Method for the Measurement and Reduction of Spectrograms for the Determination of the RadiaI Velocities of Celestial Objects''. ''Application to a Study of the Variable Star W Sagittarii''" and he received his doctorate in 1905. He joined the

Allegheny Observatory The Allegheny Observatory is an American astronomical research institution, a part of the Department of Physics and Astronomy at the University of Pittsburgh. The facility is listed on the National Register of Historic Places (ref. # 79002157, ad ...

in 1905, working with

Frank Schlesinger Frank Schlesinger (May 11, 1871 – July 10, 1943) was an American astronomer. His work concentrated on using photographic plates rather than direct visual studies for astronomical research. Biography Schlesinger was born in New York City and a ...

and moved to the University of Michigan in 1907 where he became assistant professor of astrophysics. In 1918 he became a full professor and in 1927 he succeeded William Hussey, upon his death, as director of the Observatory of the University of Michigan. During

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

, he was involved in training soldiers on navigation. He confirmed a third component to the star

Algol ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by the ...

based on spectra. He also took an interest in fishing, golf and music and had been married to Marie Louise Welton from 1920. He died from an embolism after suffering briefly from pleurisy.

References

External links

University of Michigan
{{DEFAULTSORT:Curtiss, Ralph Hamilton 1880 births 1929 deaths American astronomers University of Michigan faculty University of California, Berkeley alumni