Armillary Sphere Bookends

Hellenistic Greeks invented and used armillary spheres in the third century as a way to understand the horizon, meridian, equator, tropics and polar circles of the earth. They function as skeletal globes.

To read an armillary sphere, first familiarize yourself with the parts. The ring along the base is the horizon. On the armillary, the outermost ring is the meridian, while the largest inner ring is the ecliptic ring. Locate the date on the ecliptic ring and place a marker that represents the sun on it. Turn the sphere to trace the path the sun will take on that day. Use the markings on the horizon to find the ascension of the sunrise, and the ecliptic ring to find out the elevation of the sun at noon. Find a collection of armillary spheres on 1stDibs.