On Sizes and Distances

On Sizes And Distances

On Sizes and Distances (Περὶ μεγεθῶν καὶ ἀποστημάτων – Peri megethon kai apostematon) is a text by the ancient Greek astronomer Hipparchus. It is not extant, but some of its contents have been preserved in the works of Ptolemy and his commentator Pappus of Alexandria. Several modern historians have attempted to reconstruct the methods of Hipparchus using the available texts.