Answer:He used the geocentric and epicentric model to explain the the motion of planets and the retrograde motion
Explanation:Being a Greek scientist,he assumed that the earth Geo was the center of the universe 'centric' .
He postulated that the planets,sun and the moon revolves in small circle called epicycles whose center also revolve around the earth center called the defferent.the occassionally retrograde or seemingly backward motion of the planets,he explained is caused when a faster inner planetary body move faster than a relatively slower outer planets, then it appears that the outer body is retrogrades or moving back ward
