Tycho Brahe in front of his house in Copenhagen. Tycho Brahe left Hven in 1597, bringing some of his instruments with him to Copenhagen, and entrusting others to a caretaker on the island. Shortly before leaving, he completed his star catalogue giving the positions of 1,000 stars. After some unsuccessful attempts at influencing the king to let him return, he finally acquiesced to exile, but he wrote his most famous poem "Elegy to Dania" in which he chided Denmark for not appreciating his genius. The instruments he had used in Uraniborg and Stjerneborg were depicted and described in detail in his book
Two-body problem in general relativity The Kepler problem derives its name from Johannes Kepler, who worked as an assistant to the Danish astronomer Tycho Brahe. Brahe took extraordinarily accurate measurements of the motion of the planets of the Solar System. From these measurements, Kepler was able to formulate Kepler's laws, the first modern description of planetary motion: Kepler published the first two laws in 1609 and the third law in 1619. They supplanted earlier models of the Solar System, such as those of Ptolemy and Copernicus. Kepler's laws apply only in the limited case of the two-body problem. Voltaire and Émilie du Châtelet were the