Diagram of the solstices and equinoxes — "This diagram shows the positions of the Sun on the days of the solstices and equinoxes. The center constitutes the observer’s position, facing south (the diagram’s top). The thin yellow band framing the diagram is the horizon. Six yellow circles connected by three red arcs of decreasing size indicate sunrise (left) and sunset (right) at the summer solstice, the spring and autumn equinoxes, and the winter solstice respectively, while the arcs themselves show the Sun’s path above the horizon on these days. At the arcs’ midpoints are the midday Suns of the solstices and equinoxes. Six straight red lines on either side of the midday Suns indicate the Sun’s positions at the third and ninth hours on these days."

Featured on PDR in the collection Cosmography Manuscript (12th Century)

This wonderful series of medieval cosmographic diagrams and schemas are sourced from a late 12th-century manuscript created in England. Coming to only nine folios, the manuscript is essentially a scientific textbook for monks, bringing together cosmographical knowledge from a range of early Christian writers such as Bede and Isodere, who themselves based their ideas on such classical sources as Pliny the Elder, though adapting them for their new Christian context. As for the intriguing diagrams themselves, The Walters Art Museum, which holds the manuscript and offers up excellent commentary on its contents, provides the following description: