The planets were thought by Ptolemy to orbit Earth in deferent and epicycle motions. In the Hipparchian system the epicycle rotated and revolved along the deferent with uniform motion. For the Moon, he used a deferent and epicycle model. The equatorium was designed on the principles of epicycle and deferent. This could not have been accomplished with deferent/epicycle methods. Ptolemy emphasised that the epicycle motion does not apply to the Sun. An epicycle with one cusp is a cardioid, two cusps is a nephroid. The epicycle center moves at a constant rate in a counter clockwise direction. The equatorium can further be specialized depending on the epicycle. In fact, he did this separately for the eccentric and the epicycle model.