What did ptolemy discover?

The Central Rappahannock Regional Library also says Ptolemy used geometry to predict the movement of the planets (though he believed they revolved around the Earth). He cataloged 1,022 stars. His book "The Almagest" was the cornerstone of astronomy for many centuries. read more

Hello, I'm a student from Harvard University and just last week we where talking about this. Ptolemy first discovered his theory in the year 100 B.C and accepted later. read more

Ptolemy also measured how lines of sight are refracted at the boundary between materials of different density, such as air, water, and glass, although he failed to discover the exact law relating the angles of incidence and refraction (Snell’s law). read more