Astronomical Images : The Sun, the orb of the Earth and the sphere of the fixed stars

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. Making no concession to the geocentric cosmology, Kepler introduces the reader of the <i>Epitome</i> to a distinctly Copernican cosmology. The first image of the cosmos presented in the work is reduced to a few significant elements and depicts at its centre a large conspicuous Sun. A similar, yet even more simplified cosmological diagram is found later in the book, and reproduced here. Featuring only a central Sun, surrounded by the orbit of the Earth and the sphere of the fixed stars, this image (repeated in other parts of the book) strongly contrasts with the corresponding representations in traditional textbooks on spherical astronomy, which depict the fourteen stages of the cosmos (four elemental and ten celestial).</p>