Ptolemy's compendium, later known as the Almagest, dominated Western astronomy for 15 centuries. It was also wrong, and it took the fall of an empire to fix it. A basic understanding of the solar ...

Around the second century C.E., the Greek astronomer Claudius Ptolemy listed 48 "official" constellations in his book Almagest. No original copy of Almagest has survived, so we don't know how he ...