How did Copernicus’s model use uniform circular motion?

Nicolaus Copernicus maintained the ancient astronomical premise that planetary motion must consist of uniform circular motion. While he revolutionized astronomy by placing the Sun at the center of the solar system, he rejected the Ptolemaic system's use of the equant—an imaginary point that allowed for varying speeds—because he believed it violated the philosophical requirement that celestial rotations occur at a constant speed.123

To achieve this uniform motion while still accounting for observed planetary irregularities, Copernicus utilized a system of epicycles and deferents. He notably employed a technique similar to one developed by Persian astronomers at Marāgheh, which involved combining two uniformly revolving epicycles to generate an oscillating point. By coordinating these circular paths, Copernicus was able to model planetary movements without relying on the controversial equant, thereby preserving the principle of uniform circular motion within his heliocentric framework.21