He created a sophisticated mathematical model to fit observational data which before Ptolemy's time was scarce, and the model he produced, although complicated, represents the motions of the planets fairly well.
Siya ay nilikha ng isang sophisticated na matematiko modelo upang magkasya sa pagmamatyag ng data na bago Ptolemy ng oras ay mahirap, at ang mga modelo niya ginawa, kahit na kumplikado, kumakatawan sa motions ng planets may kabutihan.