Calculating with Andreas Aurifaber: A New Source for Copernican Astronomy in 1540

Abstract

In an article recently published in this journal, Jonathan Green announced his discovery of the earliest known printed astrological practica that mentions Copernicus. Apparently extant in a single copy, this Practica auff das Jar M.D.XLI. durch Magistrum Andream Aurifaber gestellet claims to have been computed "from the tables of Nicholas Copernicus" (Figure 1). 1 Although this imprint has been known, bibliographically, since at least 1874, no one before Green, to the best of my knowledge, noticed the remarks about Copernicus in its dedication, although previous historians have documented biographical links between the practica's author, Andreas Aurifaber (1514-59), and several well-known early Copernicans. Was Aurifaber's practica indeed "Copernican"? Might it be possible, from quantitative material therein, to reconstruct the "Copernican tables" from which it claims to have been computed? And might such a reconstruction, based on a source printed three years before the publication of Copernicus's De revolutionibus, shed light on the chronology of the composition of this latter book? Green hinted at these questions but did not pursue them; to do so is the goal of this paper. 2 Consisting of thirteen folios filled with the usual astrological content found in the dozens of German practica editions printed in the 1530s and 1540s, Aurifaber's little pamphlet perhaps not surprisingly escaped notice before Green's discovery. But many threads tie the 1541 practica and its author to Copernicus and the early Copernicans. With its dedicatory letter to the Danzig City Council dated 11 November 1540, this practica probably was printed in late November or December. The colophon identifies the printer as Franz Rhode of Danzig, who had issued Georg Joachim Rheticus's Narratio prima earlier that year. 3 Not a vigorous printing centre, Danzig had only three printshops active in the sixteenth century; Aurifaber's was the only annual calendar, almanac or practica to have been printed in that city before 1580. 4 Against this paucity of astronomical publishing in Danzig, Rhode's two 1540 imprints hence stand out sharply.As Green noted, Aurifaber had met Rheticus in the 1530s at the University of Wittenberg, where both men studied under Philipp Melanchthon. In 1539, as Rheticus headed north to Frauenburg, Aurifaber on Melanchthon's recommendation became first rector of the newly opened St Mary's Latin School in Danzig (about 60 km west of Frauenburg). At Rheticus's request, Aurifaber in February 1540 sent Melanchthon a few sheets from the Narratio prima, then being printed. In April 1540, upon receiving his copy of the Narratio, Duke Albrecht von Hohenzollern described the work as "issued by Magister Joachim Rheticus with his assistant Magister Andreas Aurifaber, schoolmaster in Danzig". Modern editors of the Narratio have suggested