From his new astronomy, using Tycho’s observations, Kepler calculated these tables of the positions of the Sun, Moon and planets. Kepler adopted John Napier’s recently invented computational method of logarithms, published in 1614. Although Kepler’s tables were assumed by many to be more accurate than others, given that they rested upon Tycho’s data, in practice the logarithms were tedious and cumbersome to use. Kepler also included Tycho Brahe’s catalog of 1,000 fixed stars, a chronological synopsis, and a list of geographical positions.