(b. Cologne, Germany, 25 November 1858; d. Potsdam, Germany, 20 December 1913)
Scheiner was the son of Jacob Scheiner, a painter of landscapes and architectural subjects. In 1878 he entered the University of Bonn to read mathematics and natural science. While there he developed an interest in astronomy, which led to his becoming an assistant at the Bonn observatory. In 1882 he obtained the doctorate with a dissertation on the observations of Algol made by E. Schonfeld, then director of the observatory. Scheiner continued to work at the observatory until moving, early in 1887, to the Royal Astrophysical Observatory at Potsdam, where he remained for the rest of his life, rising from assistant to permanent assistant to senior observer (1900). In 1894 Scheiner was appointed extraordinary professor of astrophysics at the University of Berlin.
While at the Bonn observatory Scheiner was engaged primarily in assisting in zone observations. On moving to Potsdam he immediately set to work in astrophysics, the latest, and flourishing, branch of astronomy. He collaborated closely with Potsdam’s director, Hermann Vogel, in applying the new instrument that Vogel had designed and named the spectrograph. Together they inaugurated the era of accurate measurement of stellar radial velocities. Their average probable error was only 2.6 kilometers per second, an improvement over earlier results by a factor of ten.
From the early 1890’s Scheiner was also much occupied with celestial photography and with the preparation of the international astrographic chart. In connection with the latter he represeted the Potsdam observatory at meetings in Paris in 1891, 1896, and 1900, and supervised the publication of six large volumes during the period 1899–1912. Work on the chart also benefited in several respects from Scheiner’s considerable practical and experimental skills. For example, he tested the previously employed law of photographic photometry and showed it to be incorrect.
Around the turn of the century the close relations between Scheiner and Vogel became impaired, and afterward Scheiner worked in collaboration with J. Wilsing. Among other things they made a photometric determination of the relative intensities of the three principal lines in the nebular spectra and measured visually the radial velocities of nine of the brighter gaseous nebulae. Availing themselves of recent advances in the study of blackbody radiation, they also made determinations of the temperatures of more than 100 stars.
Scheiner’s strengths lay in the experimental and practical areas of research. Drawing on his rich knowledge of both laboratory and workshop, he could quickly devise an experiment for settling a debated point. Scheiner was also an excellent teacher and enjoyed giving numerous popular accounts of astrophysical matters, both in lectures and in writing.
I. Original Works. Scheiner’s more important books are Die Spectralanalyse der Gestirne (Leipzig, 1890), translated into English by E. B. Frost (Boston, 1890), a textbook on stellar physics; Photographie der Gestirne (Leipzig, 1897), at the time considered indispensable to those interested in any branch of the subject; Strahlung und Temperatur der Sonne (Leipzig, 1899), valuable for discussion of the temperature of the sun, in light of contemporary studies of blackbody radiation; Populäre Astrophysik (Leipzig—Berlin, 1908), Scheiner’s 1906 lectures at Berlin; and Spectralanalytische und photometrische Theorien (Leipzig, 1909), meant for those with a general interest in astrophysics.
Scheiner’s more important papers are discussed by J. Wilsing (see below).
II. Secondary Literature. See E. B. Frost, “Julius Scheiner,” in Astrophysical Journal, 41 (1915), 1–9; Hector Macpherson, Jr., Astronomers of Today and Their Work (London, 1905), 234–239; and J. Wilsing, “Julius Scheiner,” in Vierteljahrsschrift der Astronomischen Gesellschaft, 49 (1914), 22–36.