How did Ptolemy improve Aristotle model?

Ptolemy improved Aristotle's geocentric model of the universe by introducing a more complex system of epicycles and deferents to account for the apparent retrograde motion of planets. While Aristotle's model was relatively simplistic, Ptolemy's adjustments provided a more accurate framework for predicting planetary positions. His work, particularly in the "Almagest," laid the groundwork for centuries of astronomical study until the heliocentric model eventually replaced it.