Notes and Reflections on Books and Media
by Hannah Leitheiser
#astronomy #epicycle #Ptolemy #Kepler
The Remarkable Science of Ancient Astronomy
Dr. Bradley Schaefer
A path given by a circle within a circle can create an elliptical orbit (proof left to the reader), but will not follow Kepler's second law requiring equal areas swept in equal time. However a Ptolemaic system of circles can be worked out with a bit of algebra, a ruler, and protractor. The planetary orbits are nearly circular, so a few arcminutes will be the extent of your reward for doing Newton's differential calculus.