He also served as court astrologer to General Wallenstein, court mathematician to Rudolf II, and assistant to Tycho Brahe, inheriting Tycho's data after his death.
This man did work in optics, validating discoveries of Galileo.  He also served as court astrologer to General Wallenstein, court mathematician to Rudolf II, and assistant to Tycho Brahe, inheriting Tycho's data after his death. For ten points, name this German, who after discovering a 1604 supernova that bears his name derived from Tycho's observations his laws of planetary motion.
This man did work in optics, validating discoveries of Galileo.  
Johannes{ Kepler}