Brahe, Tycho
1546–1601
Danish astronomer

Before the invention of the telescope, Danish noble Tycho Brahe mapped the stars far more accurately than any previous astronomer. Tycho's theories of the heavens were inaccurate. However, the data that he gathered helped to explain the structure of the solar system.

After completing his university education, Tycho studied alchemy*. However, a strange event on November 11, 1572, drew him to astronomy. That evening he noticed a bright new star in the constellation of Cassiopeia. Since this was supposed to be a "perfect," or unchanging, area of the heavens, Tycho knew he was witnessing something special. He carefully observed the new star and published his findings a year later in a book titled De Stella Nova (the new star). The work made him famous.

In 1576 the king of Denmark, Frederick II, granted Tycho an island on which to conduct his observation of the heavens. In return, Tycho was to give the king advice on astrology*. Tycho built a richly furnished, well-equipped villa* on the island. He called it Uraniborg, or the castle of astronomy. It served as both an astronomical observatory and a laboratory for his work in alchemy.

Tycho had found errors in existing measurements of the movements of the Sun, Moon, planets, and stars. He reasoned that these errors were why many astrological predictions of his day were flawed. Therefore, he designed and built his own astronomical instruments, making them very large to increase their accuracy. Tycho carefully tested these tools to be certain that they were precise. He also established new methods of computing.

The astronomical data Tycho collected were twice as accurate as any before this time. His findings led him to propose a new model of the universe. Like earlier scholars, Tycho believed that Earth stood at the center of the universe and the Sun revolved around it. However, like the Polish astronomer Nicolaus Copernicus, Tycho claimed that the other planets revolved around the Sun, not around the Earth. Copernicus argued that Earth, too, revolved around the Sun, but Tycho's observations did not appear to support this theory. Tycho's system was popular among Catholic astronomers and philosophers during the 1600s. The Catholic Church at that time rejected the idea that Earth was not the center of the universe.

When Frederik II died, his heir took away the grants that the king had awarded to Tycho. Tycho set up a new observatory near Prague, but he died soon afterward. His pupil Johannes Kepler would later use Tycho's findings to explain how planets orbit the Sun on oval-shaped paths.

* alchemy

early science that sought to explain the nature of matter and to transform base metals, such as lead, into gold

* astrology

study of the supposed influences of the stars and planets on earthly events

* villa

luxurious country home and the land surrounding it

see color plate 1, vol. 4