Tycho Brahe produce much of his astronomical data, Tycho relied heavily on the then new technique of "prosthaphaeresis", an algorithm for approximating products based on trigonometric identities that predated logarithms. Although Tycho admired Copernicus and was the first to teach his theory in Denmark, he was unable to reconcile Copernican theory with the basic laws of Aristotelian physics, that he considered to be foundational. He was also critical of the observational data that Copernicus built his theory on, which he correctly considered to have a high margin of error. Instead, Tycho proposed a "geo-heliocentric" system in which the Sun and Moon orbited
Tycho Brahe manuscripts, on locally made paper with his own watermark. He created a system of ponds and canals to run the wheels of the paper mill. Over the years he worked on Uraniborg, Tycho was assisted by a number of students and protegés, many of whom went on to their own careers in astronomy: among them were Christian Sørensen Longomontanus, later one of the main proponents of the Tychonic model and Tycho's replacement as royal Danish astronomer; Peder Flemløse; Elias Olsen Morsing; and Cort Aslakssøn. Tycho's instrument-maker also formed part of the scientific community on the island. He observed the great