Tycho Brahe (1546-1601)

Danish nobility; lost nose in duel (so had metal one). Got King Frederick II to give him a little island and build the world’s best observatory on it.

Uraniburg

Designed, built and used very accurate instruments for measuring sky positions. Kept voluminous records for years. Hired Kepler to try to understand motion of Mars. Had model with Sun going around Earth, but planets orbit Sun. Found that comets moved between planetary orbits (not Ptolemaic). Motion of Mars still not fully explained. Fell out of favor; moved.