When genius met data: Kepler’s first exploration of Tycho’s observations

This paper provides a comprehensive summary of Johannes Kepler's research during his first tenure at Benatky, from February to June 1600. For the first time, Kepler had unrestricted access to Tycho Brahe's precise Mars observations, enabling him to test and refine his theories of planetary motion. Kepler aimed to resolve inconsistencies in Tycho’s Mars model, particularly its failure to predict parallactic observations accurately. Over the four months, he developed innovative methods, such as combining observations to triangulate distances and employing Tycho’s model as a generator of reliable heliocentric longitudes. Despite numerous mathematical errors and theoretical missteps, Kepler laid the groundwork for the revolutionary ideas he would later present in Astronomia Nova. This paper highlights Kepler’s creative and exploratory approach, his use of Tycho’s data, and the significant progress he made in understanding Mars’ orbit, even as many of his early hypotheses were ultimately discarded.