Celestial planispheres. 18th-century astronomy diagrams centred around planispheres of stars and constellations. The northern celestial hemisphere is at left, with the southern celestial hemisphere at right, separated by a scale of star magnitudes. The Copernican heliocentric system (bottom centre) replaced the Ptolemaic geocentric system (top centre). In the corners are the Tychonic system (top left), the lunar phases (bottom left), the motion of the Earth around the Sun (bottom right), and the lunar tides (top right). This page is from 'Planisphaerium coeleste' (1772) by the German cartographer Tobias Conrad Lotter (1717-1777).