Rudolphine Tables

The Rudolphine Tables (Latin: Tabulae Rudolphinae) consist of a star catalogue and planetary tables published by Johannes Kepler in 1627, using some observational data collected by Tycho Brahe (1546–1601). The tables are named as "Rudolphine" in memory of Rudolf II, Holy Roman Emperor.

Star tables had been produced for many centuries and were used to establish the position of the planets relative to the fixed stars (particularly the twelve constellations used in astrology) on a specific date in order to construct horoscopes. Until the end of the 16th century, the most widely used had been the Alphonsine tables, first produced in the 13th century and regularly updated thereafter. These were based on a Ptolemaic, geocentric model of the solar system. Although the Alphonsine tables were not very accurate, nothing else was available and so they continued to be used.

In 1551, following the publication of De revolutionibus orbium coelestium by Nicholas Copernicus, Erasmus Reinhold produced the Prutenic Tables based on a heliocentric model of the solar system, but these were no more accurate than the earlier tables.

Tycho Brahe had spent much of his life obtaining measurements of the position of stars and planets to a much greater degree of accuracy than had been possible previously. He wished these observations to be the basis of a new and more accurate set of star tables. Kepler was able to prepare these new tables using Tycho's observations together with a heliocentric model of the solar system and his own discovery of the elliptical orbits of the planets. Accurate computation was aided by the newly published system of logarithms, which simplified the calculations and made them less prone to errors.

...
Wikipedia