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 autopsy performed after his body was exhumed in 1901, and the 20th-century medical assessment is that his death is more likely to have resulted from uremia. The investigations in the 1990s have suggested that Tycho may not have died from urinary problems, but instead from mercury poisoning. It was speculated that he had been intentionally poisoned. The two main suspects were his assistant, Johannes Kepler, whose motives would be to gain access to Brahe's laboratory and chemicals, and his cousin, Erik Brahe, at the order of friend-turned-enemy Christian IV, because of rumors that Tycho had had an affair with Christian's