Earth Moon at first quarter To Sun Angular separation between sun and moon when moon is at first quarter is so close to 90 (89.5) that it could not be reliably measured in ancient times Right angle Problem with Aristarchus' Method
{"Image DocumentName": "Problem with Aristarchus\u2019 Method", "Image ImageDescription": "Earth. Moon at first quarter. To Sun. Angular separation between sun and moon when moon is at first quarter is so close to 90 (89.5) that it could not be reliably measured in ancient times. Right angle. Problem with Aristarchus\u2019 Method.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}