Early Astronomy in the University of Michigan Collections

Johann Müller of Königsberg, also known by his Latin last name, Regiomontanus, was one of the most important astronomers of the fifteenth century. Born in the town of Königsberg in 1436, Regiomontanus was educated at the Universities of Leipzig and Vienna. At the latter University he became the pupil and close friend of the Austrian astronomer, mathematician, and instrument maker, Georg Peuerbach. In 1460, during a diplomatic mission in Vienna, the renowned Greek humanist, Cardinal Basilios Bessarion, sought out the expertise of Peuerbach to undertake a new improved Latin translation of Ptolemy’s Almagest. Peuerbach died suddenly in 1461, but, through the strong recommendation of his mentor, Regiomontanus would join Bessarion’s household, spending the next four years traveling in Italy, where he met outstanding Italian mathematicians like Giovanni Bianchini and Paolo dal Pozzo Toscanelli. Between 1467 and 1471, Regiomontanus worked in Hungary, first for the archbishop of Esztergom and subsequently for the court of King Mathias Corvinus in Buda. With the assistance of the Hungarian court astronomer, Martin Bylica, Regiomontanus wrote various trigonometrical and astronomical tables. In 1471, he moved to the city of Nuremberg, where he founded the first printing shop exclusively devoted to the publication of scientific works. In 1472, he published his first astronomical textbook, the Theoricae novae planetarum by Georg Peuerbach.

First published in Nuremberg in 1474, and with only a few adjustments to the predictions of the Alphonsine Tables, Regiomontanus’Ephemerides contains the calculations of the expected planetary positions, the positions of the Sun and Moon, the new and full moons, and the eclipses, all of which were predicted for the period from 1475 to 1506. One of the greatest novelties of the Ephemerides was that it provided daily planetary positions for the first time, instead of the customary calculations provided between five and ten days. Shown here is a page from our copy of the 1481 edition published in Venice by the German printer Erhard Ratdolt.

The Tables of Directions

Astronomical Tables