Question

what is epicyclic model​

Answer 1

Answer:

Apollonius. In mathematics: Applied geometry. Apollonius introduced an alternative “epicyclic” model, in which the planet turns about a point that itself orbits in a circle (the “deferent”) centred at or near Earth. As Apollonius knew, his epicyclic model is geometrically equivalent to an eccentric.

Answer 2

In the Hipparchian, Ptolemaic, and Copernican systems of astronomy, the epicycle (from Ancient Greek: ἐπίκυκλος, literally upon the circle, meaning circle moving on another circle) was a geometric model used to explain the variations in speed and direction of the apparent motion of the Moon, Sun, and planets.