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
Tycho Brahe current observational data was a day off. He realized that more accurate observations would be the key to making more exact predictions. He purchased an ephemeris and books on astronomy, including Johannes de Sacrobosco's "De sphaera mundi", Petrus Apianus's "Cosmographia seu descriptio totius orbis" and Regiomontanus's "De triangulis omnimodis". Jørgen Thygesen Brahe, however, wanted Tycho to educate himself in order to become a civil servant, and sent him on a study tour of Europe in early 1562. 15-year old Tycho was given as mentor the 19-year-old Anders Sørensen Vedel, whom he eventually talked into allowing the pursuit of astronomy during