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
Armillary sphere the crown escapement which has been developed from 14th century, and is applied to gear system which had been improved until the middle of 17th century in Western-style clockwork. In particular, timing device of Song I-yŏng's Armillary Clock adopts the early 17th century pendulum clock system which could remarkably improve the accuracy of a clock. Further advances in the instrument were made by Danish astronomer Tycho Brahe (1546–1601), whose elaborate armillary spheres passing into astrolabes are figured in his "Astronomiae Instauratae Mechanica". Armillary spheres were among the first complex mechanical devices. Their development led to many improvements in techniques and