This armillary sphere, with its interlocking rings illustrated the circles of the sun, moon, known planets, and important stars as well as the signs of the zodiac and is a model of the Ptolemaic or earth-centered cosmic system. Ironically, the globe was constructed in the same year that Nicholas Copernicus (1473-1543) published his revolutionary Copernican System with the sun as the center of the solar system.
The Purpose of the Armillary Sphere
A model demonstrates how something works. One of the first models ever made was the armillary sphere, supposedly a model of the universe. By moving the armillary rings, you could demonstrate how the planets moved. However, early models had the Earth at the center of the universe. Like any model, armillary spheres were “modified” or changed with new discoveries.
Early History of the Armillary Sphere
Some sources credit Greek philosopher Anaximander of Miletus (611-547 B. C.) with inventing the armillary sphere, others credit Greek astronomer Hipparchus (190 – 120 BC), and some credit the Chinese.
Armillary spheres first appeared in China during the Han Dynasty (206 B.C.-220 A.D.). One early Chinese armillary sphere can be traced to Zhang Heng, an astronomer in the Eastern Han Dynasty (25 A.D.-220 A.D.).
The exact origin of armillary spheres cannot be confirmed. However, during the Middle Ages armillary spheres became widespread and increased in sophistication.
By Jack Kramer
Gardens in geometric design were de rigueur before the 18th century. Enclosed by walls or hedges, each typically had a centrally placed ornamental feature where its paths met. Sculptures or fountains of all kinds usually filled this space.
Eventually an ornamental pedestal with a sundial became the popular centerpiece. For the manor house or mansion, sundials in the garden began to replace the usual statuary.
In the 18th century the armillary sundial became popular. It was favored because of its ornamental appearance in the garden. More sculpture than timepiece, it’s closely akin to the horological or time-telling sphere. The armillary dial is a sphere surrounded by rings (the word armillary comes from the Latin word for bracelet or hoop). These rings revolve around each other and about the Earth or the sun. They represent circles of celestial spheres. One ring serves as the equator. It’s pierced by an arrow—the Earth’s axis.