Kepler used the observations and data of which scientist to formulate his laws of planetary motion?

Kepler used the observations of Tycho Brahe to formulate his laws of planetary motion. Kepler worked for Tycho in his lab during his younger years. Tycho liked Kepler's intelligence, and he respected his spunk, so he gradually showed him more and more of his precious measurements. This data was crucial in the development of Kepler's laws of planetary motion.