In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. … See more

Celestial spheres (or celestial orbs) were envisioned to be perfect and divine entities initially from Greek astronomers such as Aristotle. … See more

The ancient Greeks assumed the literal truth of stars attached to a celestial sphere, revolving about the Earth in one day, and a fixed … See more

Observers on other worlds would, of course, see objects in that sky under much the same conditions – as if projected onto a dome. Coordinate … See more

Because astronomical objects are at such remote distances, casual observation of the sky offers no information on their actual distances. All … See more

These concepts are important for understanding celestial coordinate systems, frameworks for measuring the positions of See more

A celestial sphere can also refer to a physical model of the celestial sphere or celestial globe. Such globes map the constellations on the outside of a sphere, resulting in a mirror … See more