RITCHEY, GEORGE WILLIS

(b. Tupper’s Plains, Ohio, 31 December 1864; d. Azusa, California, 4 November 1945)

astronomy.

The son of an amateur astronomer and instrument maker. Ritchey acquired a practical knowledge of astronomy as a youth. After completing his formal education at the University of Cincinnati in 1887, he became an instructor at the Chicago Manual Training School, remaining there until 1896. Because his ability had impressed George Ellery Hale, he was asked to become chief optician at the newly founded Yerkes Observatory, in which capacity he adapted the 40-inch refractor for photography. From 1901 to 1906 he was on the astronomy faculty at the University of Chicago, and in 1904 he was elected an associate of the Royal Astronomical Society. In 1906, again at the request of Hale, Ritchey became the head of instrument construction at another new observatory, Mt. Wilson. There he almost singlehandedly produced the 60-inch telescope and did most of the work on the 100-inch disk for the Hooper telescope.

During World War I, Ritchey trained over 100 people to make optical parts for gunsights for the U.S. Ordnance Department. At the end of the war. following a bitter controversy at Mt. Wilson, Ritchey was dismissed from the staff because of a health problem and for allegedly exceeding his authority. He spent the next five years at his private laboratory in California, continuing the work he had started at Mt. Wilson, particularly on the development of cellular mirrors.

In 1923 Ritchcy was invited by the National Observatory in Paris to discuss some of his recent innovations; later, he became director of the observatory’s astrophotographic laboratory. While in Paris, Ritchey, with Henri Chrétien, perfected a design for an aplanatie reflector. Upon completion of the first such telescope in 1930, Ritchey was made a knight of the Legion of Honor. He returned to the United States in 1931 to become director of photographic and telescopic research at the U.S. Naval Observatory, where he began construction of a 40-inch Ritchey-Chrétien reflector. When it was completed in 1936, he retired to Azusa, California.

Ritchey not only fashioned some of the largest instruments of his, era but also used them to make important astronomical contributions; moreover, his meticulous care in observing was almost unequaled. He demonstrated the similarity between the dark lanes in the Milky Way and the Andromeda nebula (M31) and he resolved (he outer portions of M31 into individual stars. In 1917 Ritchey photographed novae (and supernovae) in M31, thereby facilitating the first reasonably accurate measurement of the distance to a spiral nebula.

BIBLIOGRAPHY

I. Original Works. Ritchey’s chief articles include “Celestial Photography With 40-Inch Visual Telescope of the Yerkes Observatory,” in Astrophysical Journal, 12 (1900), 352–360; “On Some Methods and Results in Direct Photography With the 60-Inch Reflecting Telescope of the Mount Wilson Solar Observatory,” Ibid., 32 (1910), 26–35; and “The Thomas Young Oration: The Modern Reflecting Telescope and the New Astronomical Photography,” in Transactions of the Optical Society, 29 (1927–1928), 197–224. Ritchey’s longest work, which was published late in his professional life and summarized much of his career, laid plans for an ambitious eight-meter telescope: The Development of Astro-Photography and the Great Telescope of the Future (Paris, 1929), published by the Soeiété Astronomique de France.

II. Secondary Literature. For biographical information on Ritchey, see J. McKeen Cattell and Jacques Cattall, American Men of Science (New York, 1938), 1189; and G. Edward Pendray, Men, Mirrors and Stars (New York, 1935), 127–135, 222–228, 235–237, 259, 267–268, also in rev. ed. (New York, 1946), 223–238, 266, 269, 305–306. There are brief obituaries by Dorrit Hoffleit, in Sky and Telescope, 5 (1946), 11; and by F. J, Hargreaves, in Monthly Notices of the Royal Astronomical Society, 107 (1907), 36–38. Private, polemical correspondence both with and about Ritchey is in “The George Ellery Hale Papers, 1882–1937,” microfilm ed. prepared at California Institute of Technology (Pasadena, 1968).

Richard Berendzen