Burnham, Sherburne Wesley

(b. Thetford, Vermont, 12 December 1838; d. Chicago, Illinois, II March 1921)

astronomy.

Burnham, an indefatigable observer, was a selftrained amateur astronomer. His formal education ended with his graduation from Thetford Academy. He then became an accomplished shorthand reporter and, except for six months spent at the Washburn Observatory and four years at the Lick Observatory, worked full time in law courts until his retirement at age sixty-four in 1902. Form 1897 to 1914 Burnham was professor of practical astronomy at the Yerkes Observatory, living in Chicago and commuting to Williams Bay, Wisconsin, for two nights each week to use the forty-inch telescope, For his astonomical work Burnham was honored by the Royal Astronomical Society (member, 1874; associate, 1898; Gold Medal, 1894) and the Académie des Sciences (Prix Lalande, 1904), and by Yale (M.A., 1878) and Northwestrn (Sc.D., 1915) universities.

Burnham’s significant contributions to the study of double stars were the discovery of numerous visual binary systems, the measurement of their separation and postion angles, and a critical compilation of information concerning all known northern pairs, When Burnham began observing in 1870, it was commonly assumed that the Struves and Herschels had found most of the binaries visible in the Northern Hemisphere. With the aid of excellent telescope lenses figured by Alvan Clark & Sons, as well as extraordinarily keen vision, Burnham proved otherwise, Indeed, many of his discoveries were new companions of stars or star systems that had already been carefully scrutinized. The culmination of these efforts came in 1900, with the Publication of A General Catalogue of 1290 Double Stars Discovered from 1871 to 1899 by S.W. Burnham.

Burnham devoted most of his time at large telescopes to measuring diffcult pairs—those with separations less than 1″ and those of unequal magnitudes. He also measured the positions of components of suspected binaries relative to background stars for evidence of common proper motion, and hence of physical relation. For these measurements Burnham designed and used a filar micrometer with greatly improved bright-wire illlumination. To help identify his discoveries Burnham compiled, and finally published, A General Cataogue of Double Stars Within 121° of the North Pole, the first comprehensive and critical survey of all (13, 665) known binaries in this region.

BIBLIOGRAPHY

I. Original Works, Burnham’s writings include “The Position Micrometer of the Washburn Observatory,” in English Mechanic, 34 (1881), 39–40; A General Catalogue of 1290 Double Stars Discovered from 1871 to 1899 by S. W. Burnham, Arranged in order of Right Ascension with all the Micrometrical Measures of Each pair, Publications of the Yerkes Observatory, no, 1 (Chicago, 1900), the intoduction to which includes an often-quoted autobiography and references to his nineteen original lists of double stars; A General Catalogue of Double Stars Within 121° of the North Pole, Cotalogue Institution Publication no. 5 (Washington, D.C., 1906); and Measures of proper Motion Stars Made with the 40-Inch Refractor of the Yerkes Obsevatory in the Years 1907 to 1912, Carnegie Institution Publication no. 168 (Washington, D.C., 1913).

II. Secondary Literature. Works on Burnham consist primarly of obituaries written by his colleagues and published in various astronomical journals.

Deborah Jean Warner