How did Copernicus explain retrograde motion differently from Ptolemy?

Copernicus explained retrograde motion by introducing a heliocentric model of the solar system, where the Earth and other planets orbit the Sun. In this framework, retrograde motion is observed when Earth, which travels at a faster orbital speed, overtakes an outer planet. As Earth moves ahead, that outer planet appears to move backward against the background stars from our perspective on Earth. This explanation eliminates the complexity of multiple epicycles that Ptolemy relied on in his geocentric model, where retrograde motion was explained through intricate circular paths within circular orbits. By redefining the motion of planets based on their relative positions and speeds, Copernicus provided a simpler and more accurate understanding of retrograde motion.