SCHAEBERLE, JOHN MARTIN

(b. Württemberg, Germany, 10 January 1853); d. Ann Arbor, Michigan, 17 September 1924)

practical astronomy.

Schaeberle’s most important work was with astronomical particularly for astronomical photography; he figured mirrors and constructed telescopes; he investigated instrumental errors and atmospheric conditions; and he used instruments to good advantage. For this he was well trained, first as a machinist’s apprentice and later as a civil engineer at the University of Michigan. Following graduation in 1876, Schaeberle spent twelve years at the university observatory before moving to Mt. Hamilton, California, as one of the original staff members of the Lick Observatory. For a brief period in 1897 Schaeberle served as acting director of Lick; then, after traveling around the world, he retired to Ann Arbor.

Schaeberle’s early studies of comets included computations of their orbits and, with the aid of reflecting telescopes of his own construction, the discovery of two comets in 1880 and 1881. At Lick, Schaeberle turned to photography of stars, planets, nebulae, and solar eclipses. His visual observations led to his discovery in 1896 of the thirteenth-magnitude companion of Procyon.

During four eclipses–in California in 1889; at Cayenne, French Guiana, in 1889; at Mina Bronces, Chile, in 1893; and in Japan in 1896–Schaeberle took excellent large-scale photographs. From these he developed a mechanical theory of the solar corona (as opposed to the magnetic theories then widely discussed), according to which ejection of matter from the sun and its subsequent movement in a conic section accounted for the apparent structure of the corona.

Other theories expounded by Schaeberle, with perhaps more vigor than reason, concerned the history of the earth. He argued, for instance, that the inherent heat of the earth, not of the sun, controls the temperature of the earth, and that the sun is the parent body of the sidereal as well as of the solar system.

BIBLIOGRAPHY

The most extensive list of Schaeberle’s published articles is in the Royal Society Catalogue of Scientific Papers, XI , 297; XVIII , 477–479.

Secondary literature includes W.J. Hussey, “John Martin Schaeberel,” in Publications, Astronomical Society of the Pacific, 36 (1924), 309–312; a biography in Dictionary of American Biography, XVI , 412; and John A. Eddy, “The Schaeberle 40–ft. Eclipse Camera of Lick Observatory,” in Journal for the History of Astronomy, 2 (1971), 1–22.

Deborah Jean Warner