Copernicus and the Asr Challenge | W Aiting for Kepler | 1. Thoughts on Asr Research 1.1. Asr and the History O F Astronomy When Copernicus

When Copernicus1 introduced a heliocentric model of the solar system, assuming circular trajectories of planets around the sun, his model yielded larger errors than the well-known and rather successful Ptolemaic model (for which the sun and stars were modeled as moving around the earth in a complicated orbit). Fortunately for Humanity, these large errors did not discourage Copernicus from using his new and elegant concept. However, in order to convince his colleagues of the viability of his model, he had to apply an \engineering tweak": he postulated \epicycles", or small planetary revolutions that occurred in addition to the larger orbital motions. These tweaks, which also been used in the old Ptolemaic system, reduced the error for the new model so that it was competitive with the \successful" Ptolemaic model. Kepler later proposed a better model with elliptic planetary trajectories, which eliminated the need for the \tweak" [18].