Astronomical Images : Sphericity of the Earth and sea: the ship argument

Johannes Kepler

Astronomical Images

<p style='text-align: justify;'>Johannes Kepler's <i>Epitome astronomiae copernicanae</i> was published in three successive parts from 1617 to 1621. Intended as a new astronomical textbook for students, the <i>Epitome</i> covered much of the material traditionally associated with the <i>Theoricae planetarum</i> and works on spherical astronomy. Despite its title, the <i>Epitome</i> does not draw its information directly from Copernicus' <i>De revolutionibus</i> but is an original synthesis, mainly based on Kepler's own earlier works. It thus presents a comprehensive survey of Kepler's new astronomy. The text is illustrated by an abundance of images, with some figures printed multiple times. This figure, taken from the tradition of spherical astronomy, demonstrates the rotundity of the Earth, such that the lower part of an outward-bound ship disappears before the mast-head. It was copied from Michael Maestlin's <i>Epitome astronomiae</i> (1610), with similar figures found in earlier Venetian editions of Sacrobosco.</p>