Linked from

The 14 pages that link to Equant, each with the reason it gives.

• PtolemyBroader topic: Ptolemy used the equant to improve predictions while departing from uniform motion centered on the deferent.

• AlmagestBroader topic: Ptolemy used this device to model changing planetary speeds.

• Ptolemaic systemBroader topic: Ptolemy used it to improve predictions of changing planetary speed.

• Nicolaus CopernicusRelated: Copernicus objected to this device as inconsistent with uniform circular motion.

• Copernican heliocentrismCompared with: Copernicus rejected the equant because its uneven motion conflicted with his preferred circular uniformity.

• Ancient Greek astronomyBroader topic: Ptolemy used the equant to model nonuniform planetary motion while preserving geometric regularity.

• GeocentrismBroader topic: Ptolemy used it to improve predictions while departing from uniform motion around Earth.

• Claudius PtolemyBroader topic: Ptolemy used the equant to model changing planetary speeds while preserving uniform motion around an offset point.

• Deferent and epicycleRelated: Ptolemy added this device to improve planetary predictions beyond the deferent and epicycle alone.

• Tychonic systemRelated: Brahe's system retained some mathematical devices inherited from earlier geocentric astronomy.

• De revolutionibus orbium coelestiumCompared with: Copernicus rejected the equant as inconsistent with uniform circular motion.

• Nasir al-Din al-TusiCompared with: Al-Tusi sought alternatives to the equant’s departure from uniform circular motion.

• Copernican systemCompared with: Copernicus rejected the equant as violating uniform circular motion, though his model remained geometrically complex.

• Tusi coupleCompared with: The equant handles irregular planetary speed by a measuring point, not by converting rotations into a line.