In Ptolemy's planetary models, certain parameters for each planet held close relationship with the model of the sun. The models below illustrate these connections.

The inferior planets: Mercury and Venus, are characterized by their limited elongation with the sun. Ptolemy modeled this by placing the center of the planet's epicycle on a line between the Earth and the Sun. This gives the appearance that the Sun is driving this aspect of the planet's motion. The observed elongation between the planet and the Sun is shown. Suggested values for sliders are provided so as to reproduce the observed synodic periods of Mercury and Venus. [br][br]This model ignores the effects of the eccentric and equant constructions.

The Animate checkbox will animate the motion. The Epicycle Period slider adjusts the relative period of the planet around its epicycle relative to a tropical year. [br][br]The Deferent Size slider scales the entire model. It is measured in Astronomical Units while the Epicycle Size slider defines the radius of the epicycle relative to the radius of the deferent. [br][br]When the Animate checkbox is not checked, an Epicycle Position slider will appear allowing the user to move the planet around the epicycle. [br][br]The two buttons named Mercury and Venus will set the values of the Epicycle parameters to their respective values.

The superior planets: Mars, Jupiter, and Saturn, may have any elongation with the sun. However, they are observed to go into retrograde motion only when they are in opposition to the sun. Ptolemy modeled this by placing the planet on its epicycle in such a way that a line from the center of the epicycle to the planet is parallel to a line from the Earth to the Sun. This give the appearance that the Sun is driving this aspect of the planet's motion. The observed elongation between the planet and the Sun is shown. Suggested values for sliders are provided so as to reproduce the observed synodic periods of Mars, Jupiter, and Saturn. [br][br]This model ignores the effects of the eccentric and epicycle constructions.

The Animate checkbox will animate the motion. The Tropicle Period slider adjusts the relative period of the planet around its deferent relative to a tropical year. [br][br]The Deferent Size slider scales the entire model. It is measured in astronomical units (AU) while the Epicycle Size slider defines the radius of the epicycle relative to the radius of the deferent. [br][br]When the Animate checkbox is not checked, a Sun Position slider will appear allowing the user to move the Sun around its orbit. [br]