One of Tycho Brahes first contributions to astronomy was the detection and correction of several grave errors in the standard astronomical tables. Then, in 1572, he discovered a supernova located in the constellation of Cassiopeia. Eventually, his fame led to an offer from King Frederick II of Denmark & Norway to fund the construction of an astronomical observatory.
The island of Hven (now called Van) was chosen and in 1576, construction began. Tycho Brahe called the castle Uranienborg, which means fortress of the heavens. He spent twenty years there, making observations of those heavens.
After the death of his benefactor in 1588, the new king, Frederick II withdrew support for Tycho Brahe. Eventually, he was even removed from his beloved observatory. In 1597, Emperor Rudolf II of Bohemia offered him a pension of 3000 ducats and an estate near Prague, where he planned to construct a new Uranienborg. Unfortunately, Tycho Brahe died in 1601 before construction was complete.
During his life, Tycho Brahe did not accept Copernicus model of the universe. He attempted to combine it with the Ptolemaic model. He proposed that the five known planets revolved around the sun, which, along with those planets, revolved around the earth each year. The stars, then, revolved around the Earth, which was immobile.
Of course, Tycho Brahes theories were incorrect, but the data he collected during his lifetime was far superior to any others made prior to the invention of the telescope.
After Tycho Brahes death, his assistant, Johannes Kepler used Tycho Brahes observations to calculate his own three laws of planetary motion.