Tycho Brahe

Tycho Brahe was a Danish astronomer whose work in developing astronomical instruments and in measuring and fixing the positions of stars paved the way for future discoveries. His observations—the most accurate possible before the invention of the telescope—included a comprehensive study of the solar system and accurate positions of more than 777 fixed stars. In 1576 King Frederick II of Denmark granted him title to the island of Ven, about halfway between Copenhagen and Helsingør,and the financial support for establishing an observatory and laboratory. Tycho called the observatory Uraniborg, after Urania, the Muse of astronomy. For over 20 years, Brahe used the island as his base from which to make astronomical observations. Surrounded by scholars and visited by learned travelers from all over Europe, Tycho and his assistants collected observations and substantially corrected nearly every known astronomical record. To his earlier observations, particularly his proof that the nova of 1572 was a star, he added a comprehensive study of the solar system and his proof that the orbit of the comet of 1577 lay beyond the Moon. He proved that comets were not just components of Earth's atmosphere, but actual objects traveling through space. Brahe showed irregularities in the Moon's orbit and discovered a new star in the Cassiopeia formation. Brahe invented many instruments such as the Tyconian Quadrant which were widely copied and led to the invention of improved observational equipment. In 1600, Tyco Brahe hired Johannes Kepler as his assistant. He proposed a modified Copernican system in which the planets revolved around the Sun, which in turn moved around the stationary Earth. What Tycho accomplished, using only his simple instruments and practical talents, remains an outstanding accomplishment.