ocr: EPICYCLE Astronomers of antiquity explained the EPICYCLE seemingly backward motion of planets DEFERENI with epicyclic orbits. According to the epicyclic model, planets travelled on their own small circular orbits (epicyclic circles) around a centre point, which was located on the actual orbit (defer- ent). Epicycles were essential for a geo- centric world view, because the occa- sionally backward movement of planets could not be explained otherwise. The introduction of a heliocentric world view made the epicycles smaller, but Before Kepler, if was thought that all orbits in only in the 1700's ...
