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Andreas Cellarius, Atlas coelestis seu Harmonia Macrocosmica - pl. 15


Andreas Cellarius (1596-1665)
Atlas cœlestis seu Harmonia Macrocosmica, Amsterdam, 1660
Florence, Biblioteca Nazionale Centrale, Magl. 5._.81, pl. 15

An illustration of the geometrical solutions devised by Ptolemy to explain the planets' retrograde motion. The Earth is surrounded by the orbit of a single planet which advances along the epicycle, pulled by the deferent. At bottom right we see a solution based on the eccentric position of the Earth. The diagram at the bottom left shows the same solution for the movement of the Sun.