The Planisphere of [Tycho] Brahe, plate 6 from Harmonia Macrocosmica

The Danish astronomer Tycho Brahe (1546-1601) devised this complex geo-heliocentric model, which has the Sun and Moon revolving around the Earth, and the other planets orbiting the Sun. This reflected a compromise between the systems of Ptolemy and Copernicus by permitting the Earth to remain immobile at the center of the universe but accounting for some of the newly recorded observations on how the planets moved. Despite its problems (namely the intersecting orbits of Mars and the Sun), Tycho's hybrid system was favored during most of the 17th century. Tycho operated one of Europe's most advanced observatories, called Uraniborg, built on the island of Hven with the support of the Danish crown. His advanced astronomical instruments and tireless observation-he accurately measured and catalogued the position of more than 1, 000 stars-helped elevate the field of astronomy to the level of serious science.