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The equant is an off-center point around which a circle moves with uniform angular velocity, creating a non-uniform motion around the center.

When the point moving on the equant -- here the Sun but usually an epicycle -- is closer to the equant it will travel slower with respect to the center.

Here's it's highly exaggerated so you can't miss it. Most often, as the equants are generally quite small, it's noticeable only in the relationship with the sun's orbit: the equant angle will appear to wobble back and forth around the mean sun, as in Ptolemy's model of Venus.

Together the eccentric and equant can be thought of as an approximation of Kepler's second law, in which an elliptical orbit sweeps out an equal area per unit time, rather than an equal distance.

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