But as the orientation of Earth's orbit changes relative to the Vernal Equinox due to apsidal precession, the way the length of the seasons are altered by the nonuniform motion changes, since different sections of the orbit are involved.

Ptolemy discusses the correction needed to convert the meridian crossing of the Sun to mean solar time and takes into consideration the nonuniform motion of the Sun along the ecliptic and the meridian correction for the Sun's ecliptic longitude.

He had devised a way in which a single rotation would generate the several non-uniform motions.

Principles of the geometry of motion, Uniform and non-uniform motion, linkage, gears, cams.

Einstein's General Theory of Relativity describes the effect on space and time measurements of an observer, either imbedded in a gravitational field or else undergoing non-uniform motion.

The uniformity was generally assumed to be observed from the center of the deferent, and since that happens at only one point, only non-uniform motion is observed from any other point.