Geocentric model coelestium" ("On the Revolutions of the Heavenly Spheres"), which posited that the Earth and the other planets instead revolved around the Sun. The geocentric system was still held for many years afterwards, as at the time the Copernican system did not offer better predictions than the geocentric system, and it posed problems for both natural philosophy and scripture. The Copernican system was no more accurate than Ptolemy's system, because it still used circular orbits. This was not altered until Johannes Kepler postulated that they were elliptical (Kepler's first law of planetary motion). With the invention of the telescope in 1609,
Central Europe do not clearly define the region, but Encarta places the same countries into Central Europe in its individual articles on countries, adding Slovenia in "south central Europe". The German Encyclopaedia "Meyers Grosses Taschenlexikon" ("Meyers Big Pocket Encyclopedia"), 1999, defines Central Europe as the central part of Europe with no precise borders to the East and West. The term is mostly used to denominate the territory between the Schelde to Vistula and from the Danube to the Moravian Gate. Usually the countries considered to be Central European are Austria, Croatia, the Czech Republic, Germany, Hungary, Poland, Slovakia, Slovenia, Switzerland; in the