Solar and Umbral Sizes in the Al-Khwārizmī and Peurbach Eclipse Tables
We analyze and compare the structure of two tables, the tables of al-Khwārizmī and George Peurbach’s Tabulae Eclypsium, looking at the syzygy angular velocities of the Sun and the Moon and the angular radii of the Sun, the Moon and the lunar eclipse umbra. We show that part of the underlying structure has a mediaeval Indian origin. Finally, we compare recomputed tables with Peurbach’s tables.
