Tycho Brahe

Who is Tycho Brahe?

Tycho Brahe was a Danish nobleman and astronomer born in 1546 in Scania, then part of Denmark. He is celebrated for the exceptional accuracy and completeness of his astronomical observations, made before the invention of the telescope using large, precisely built instruments. In 1572 he observed a 'new star' (a supernova) in the constellation Cassiopeia, challenging the ancient belief that the heavens were unchanging. With royal support from King Frederick II he established the observatory of Uraniborg on the island of Hven, where he compiled decades of meticulous measurements of planetary positions. He proposed a hybrid 'Tychonic' model of the cosmos in which the planets orbit the Sun while the Sun orbits a stationary Earth. His vast and precise observational data, inherited by his assistant Johannes Kepler, enabled Kepler to derive his laws of planetary motion. Brahe left Denmark after a dispute with the crown and settled in Prague, where he died in 1601.

Sources: Tycho Brahe, 'De nova stella' (1573) · Tycho Brahe, 'Astronomiae instauratae mechanica' (1598) · Victor E. Thoren, 'The Lord of Uraniborg: A Biography of Tycho Brahe' (1990)