Kepler’s New Astronomy: Ptolemy's Equant

Ptolemy caused planets to slightly change their speed throughout their orbit, by using a mathematical point called the equant. This video explains how. Kepler thought the equant was a mathematical shadow of a truly physical principle: gravitation.

[GTChow]

This has got to be hands-down the best explanation of the equant in the universe. Thank you, Master

[guilldea]

Perfect, I needed to visualize the equant and this was the best I could find. Thank you!

[eastsky]

Great! Can I use your video a little? I will put a link to you.

[vgovger]

All these problems are explained in the geo model by allowing the earth to tilt and rotate in the center of the solar system...so now we are back to square one.