and money to the study of mathematics and astronomy. Two years later when eighteen years of age, he resolved to perform anew the task of Hipparchos and Ptolemy and make a catalogue of the stars more accurate than their's. His family hotly opposed these plans; and for six years he wandered through the German states, now at Wittenberg, now at Rostock (where he fought the duel in which he lost part of his nose and had to have it replaced by one of gold and silver)[1] or at Augsburg—everywhere working on his chosen subjects. But upon his return to Denmark (1570) he spent two years on chemistry and medicine, till the startling appearance of the New Star in the constellation of Cassiopæa (November, 1572) recalled him to what became his life work.[2]
Through the interest and favor of King Frederick II, he was given the island of Hveen near Elsinore, with money to build an observatory and the pledge of an annual income from the state treasury for his support.[3] There at Uraniborg from 1576 to 1597 he and his pupils made the great catalogue of the stars, and studied comets and the moon. When he was forced to leave Hveen by the hostility and the economical tendencies of the young king,[4] after two years of wandering he accepted the invitation of the Emperor Rudolphus and established himself at Prague in Bohemia. Among his assistants at Prague was young Johann Kepler who till Tycho's death (on October 24, 1601) was his chief helper for twenty months, and who afterwards completed his observations, publishing the results in the Rudolphine Tables of 1627.
This "Phoenix among Astronomers"—as Kepler calls him,[5]—was the father of modern practical astronomy.[6] He also propounded a third system of the universe, a compromise between the Ptolemaic and the Copernican. In this the Tychonic system,[7] the earth is motionless and is the center of the orbits of the sun, the moon, and the sphere of the fixed stars, while the
