Optics by Euclid
Call Number: Vat. gr. 204, fols. 115 verso-116 recto
Publication Date: ca. 10th century
RR, Plate 110: This is the oldest and best manuscript of a collection of early Greek astronomical works, mostly elementary, by Autolycus, Euclid, Aristarchus, Hypsicles, and Theodosius, as well as mathematical works. Shown here is Proposition 13, with many scholia, concerned with the ratio to the diameters of the moon and sun of the line subtending the arc dividing the light and dark portions of the moon in a lunar eclipse.