Tychonian system

Tychonian system

Diagram depicting the basics of the Tychonian geocentric system. Basically, the objects on blue orbits (the Moon and the Sun and the fixed stars) revolve around the Earth. The objects on orange orbits (Mercury, Venus, Mars, Jupiter, and Saturn) revolve around the Sun. All is surrounded by a sphere of fixed stars (though they are fixed only with respect to each other, for the sphere revolves around the earth). The system is essentially geocentric, though everything except for the moon and the fixed stars and the earth centre itself revolves around the Sun.

Distances are of course just generalized, though it is important that the minor planets are always "tied" to the Sun while the major planets can be on either side of the Earth. This is a superior diagram of Tycho's system to most that you will find: the path of the sun's orbit intersects with the path of Mars' orbit, causing a problem for any astronomer thinking of the mechanism as incorporating nested physical "spheres".