Tycho Brahe (Scania, 1546 – Prague, 1601), a Danish astronomer, observes in November 1572 a bright nova in Cassiopeia — the first documented supernova in the Western sky since antiquity — and demonstrates through parallax that it is not located in the sublunar sphere, refuting Aristotelian cosmology's immutable heavens. He builds on the island of Hven, funded by Frederick II of Denmark, the Uraniborg observatory (1576), the most precise of the pre-telescopic era. Over twenty years he accumulates measurements of planetary and stellar positions with a precision of 1–2 arcminutes — ten times better than any earlier work. This body of data, which Brahe failed to integrate into a complete theory, is the material on which Kepler builds his three laws. Brahe proposes the "Tychonic" system as a compromise between Ptolemy and Copernicus, but his real value is the quality of his data, not his theory.