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 days The Coligny calendar also identifies certain calendar dates as lucky or unlucky, and the Roman "fasti" marks many days and parts of others as "dies nefasti", unsuited for the conduct of public business. Contemporary North America preserves a tradition that Friday the 13th is an unlucky day. It has been called a "pervasive form of divination" that "is found in all societies which regulate their days and nights in calendric systems." The received idea concerning the origin of Tycho Brahe days was that "Tycho Brahe, the celebrated Danish astronomer of the sixteenth and seventeenth centuries, was very superstitious, considering certain