Linked from

The 13 pages that link to Deferent and epicycle, each with the reason it gives.

• PtolemyBroader topic: Ptolemy used these circles to reproduce planets’ changing apparent speeds and retrograde loops.

• AlmagestBroader topic: These circles represent planetary paths within Ptolemy’s computational system.

• Ptolemaic systemBroader topic: Their combined motions form the system’s main device for matching planetary paths.

• Copernican heliocentrismRelated: Copernicus retained epicycles to represent planetary paths with combinations of uniform circular motions.

• Retrograde motionBroader topic: This device generated apparent reversals in geocentric models before heliocentrism explained them through relative motion.

• Ancient Greek astronomyBroader topic: This construction reproduced planetary loops within a broadly Earth-centered model.

• GeocentrismBroader topic: These circles reproduced retrograde motion without moving Earth.

• Claudius PtolemyBroader topic: This nested-circle construction is the signature device of Ptolemy’s planetary models.

• EquantRelated: The equant modifies the deferent’s motion in this standard model of planetary paths.

• Copernican RevolutionRelated: Copernicus retained circular devices to reproduce observed planetary paths.

• De revolutionibus orbium coelestiumRelated: Copernicus retained circular combinations to reproduce observed planetary paths.

• Nasir al-Din al-TusiRelated: Al-Tusi revised circle-based planetary models rather than abandoning their basic geometry.

• Copernican systemBroader topic: Copernicus retained this device to reproduce planetary positions while changing the system’s center.