Bürg, Johann Tobias

(b. Vienna, Austria, 24 December 1766; d. Wiesenau, Austria, 25 November 1834)

astronomy.

His parents were poor, and Bürg was destined to become a craftsman, until he received a fellowship from the Imperial Commission for Education. At Vienna University he studied mathematics and astronomy under Triesnecker and Hell. He became a physics teacher at the lyceum of Klagenfurt, Carinthia, in 1791, and the following year he returned to Vienna as assistant at the university observatory. After 1802 Bürg traveled. For two years he was calculator at the observatory of Seebergen, near Gotha, under Zach. After his return to Vienna he worked again at the university observatory and became professor of mathematics and astronomy at the university in 1806. In the same year, in a competition of the Paris Academy, he received an award for his new lunar ephemerides (see below). He became a knight of the Order of Leopold in 1808. From that year on, Bürg suffered from progressive deafness. In 1813 he took a leave of absence from his teaching duties. He hoped to succeed Triesnecker at the observatory, but Littrow was chosen. Bürg retired in 1819. He lived in Vienna until 1825, when he moved to Wiesenau, Carinthia. He never married.

Bürg began his practical astronomical observations while still a university student. After his appointment as professor he cooperated in, and was adviser to, the survey of Austria, but his main interest was calculation. He worked on the Viennese ephemerides for many years and was coeditor with Triesnecker.

Bürg was one of the leading calculating astronomers of his time, and his most important work was the recalculation of lunar ephemerides. He improved Laplace’s perturbation theory of the complicated motion of the moon by adding more terms of the perturbation function: for the influence of the sun—considered not as the central body but as a disturbing one—and for the oblateness of the earth. Thus he found in the secular motion of the moon a term with a period of about 180 years and an amount of 13.8”. Taking this into consideration and making use of more recent observations, Bürg’s lunar ephemerides proved to be much more accurate than those of his predecessors. From 1813 to 1820 they formed the basis of the lunar ephemerides in the Nautical Almanach of the British Admiralty.

BIBLIOGRAPHY

I. Original Works. Bürg’s writings include Ephemerides astronomicae anni 1794 [-1806] a Francsco de Paula Triesnecker… et Joanne Burg… supputatae (Vienna, 1793–1805); and “Tables de la lune,” in Tables astronomiques publiées par le Bureau des Longitudes (Paris, 1806). Shorter articles are in Berliner astronomisches Jahrbuch; Monatliche Korrespondenz zur Beförderung der Erd-und Himmelskunde; and Zeitschrift für Astronomie und verwandte Wissenschaften.

II. Secondary Literature. Further information on Bürg may be found in Johann Volkamer von Ehrenberg, “Johann Tobias von Bürg,” in Carinthia, 25 (1836). 66 ff.; Johann Steinmayr, S. J., “Die Geschichte der Universitäts-Sternwarte,” pt. 3 (Vienna; ca. 1935), MS at observatory of University of Vienna; Constant von Wurzbach, in Biographisches Lexikon des Kaiserhums Oesterreich, pt. 2 (1857), 196–198; and Martin Wutte, “Zum Gedächtnis des Astronomen J. T. Bürg,” in Carinthia, 124 (1934).143 ff.

Josef MayerhÖfer

Thomas Widorn