Phenomena Copernicus, published by Johann Doppelmayr in his Atlas Coelestis in 1742, shows the evolution of thought about how the solar system is laid out. Figure 1 describes how the sun illuminates the Earth at different points throughout the year, as the Earth orbits around it. Figures 2-5 depict a geocentric model of the universe. Figure 2, the Ptolemaic model, shows the four elements (earth, air, fire, and water) within the orbit of the moon. Mercury, Venus, the sun, Mars, Jupiter, and Saturn orbit outside the moon. The eighth sphere, outside Saturn's orbit, includes "fixed stars", or all stars visible from Earth. The idea of one sphere including all the stars remains consistent throughout all the represented models. Outside are three spheres controlling the motions of the system. The rest of the geocentric models adjust the order of the planets and dispense with the inner- and outermost spheres. Figure 6 is a model attributed to 17th-century Dutch theologian Johann Cocceius. Mercury and Venus orbit a central point, the Earth (seen, for the first time, to be orbited only by the moon) and sun are fixed outside the inner planets, and Mars, Jupiter, and Saturn orbit outside them. Figures 7 and 8 both build on Copernicus' heliocentric model of the solar system. Figure 7 is the first to suggest that the fixed stars, while all in one outermost sphere, varied in distance from Earth. Figure 8 has the planets orbiting around the sun, but the sun itself orbits around a true central point.