Tycho's orbital reconstruction of
the 1577 Comet

The orbital path of the 1577 comet, as reconstructed by Tycho on the basis of his observations. The comet's path is drawn within Tycho's planetary system, where all planets orbit around the Sun, with the latter orbiting a fixed Earth. Note that the comet's path crosses numerous planetary spheres, from which Tycho concluded that the said spheres could not be crystalline, solid objects as assumed by Aristotle. Like Copernicus before him, and with every astronomer of his days, Tycho clung firmly to the notion of perfectly circular orbits for all heavenly body; Kepler would be the first to break out of this mental block.

Tycho           Aristotle           Copernicus           Kepler