Theory and Observation in the Pseudo-Annular Eclipse reported near Vienna on 17 June 1433

This talk analyzes a solar eclipse that is described as annular, but that other reports and modern calculations show to have been very total. I explore the reasons for this odd state of affairs, since most eclipse observers are impressed by the darkness, not what’s happening immediately around the Sun. I argue that the report comes from a theoretically sophisticated observer with access to a 14th c. annular eclipse report that shaped his observation, which was then used to refute the concentric-sphere astronomy of al-Bitruji, an influential 12-13th century Arab astronomer.

Michael H...