Porter, Dot2023-05-232017-11-012017-10-012017-11-01https://repository.upenn.edu/handle/20.500.14332/46936http://dla.library.upenn.edu/dla/medren/pageturn.html?id=MEDREN_9950583033503681youtubePenn Library's LJS 268 - Ptolemy's Almagest (Video Orientation)Media