Johannes Kepler: Tabulae Rudolphinae

Ülm: Jonas Saur, 1627
Sp Coll Hunterian Aw.1.12

The Rudolphine tables are the fruit of both Kepler’s and Brahe’s painstaking observations, and the title clearly signals Kepler’s debt to his former master. In 1600, Kepler (1571-1630) became assistant to Tycho, who was then astronomer to Rudolf II, Holy Roman Emperor. When Tycho died shortly afterwards, Kepler succeeded to the post of imperial mathematician and so was able to use the data that Tycho had accumulated from his observations. After many years’ work, the tables were published in 1627 and dedicated to Rudolf II. They represented a great improvement on the accuracy of previous astronomical tables.

Unlike Tycho, Kepler accepted Copernicus’ heliocentric system, although he came to the conclusion that the planets moved in ellipses, not perfect circles, around the sun. In addition to providing tables of unprecedented precision, Kepler strove to discover laws for the motions of the planets around the sun. These found expression in his three laws of planetary motion, the third of which established a connection between planets’ mean distances from the sun and the period of their revolutions.  

Image: engraved frontispiece which commemorates the contributions of the great astronomers Hipparchus, Ptolemy, Copernicus and Tycho.

Go to the next book in the exhibition: Johann Hevel: Selenographia