Page "Deferent and epicycle" Paragraph 4

Despite the fact that the Ptolemaic system is considered geocentric, the planets ' motion was not thought to be actually centered on the Earth.

Instead, the deferent was centered on a point halfway between the Earth and another point called the equant.

The epicycle, meanwhile, rotated and revolved along the deferent with uniform motion.

The rate at which the planet moved on the epicycle was fixed such that the angle between the center of the epicycle and the planet was the same as the angle between the earth and the sun.