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Glossary term: Celestial Sphere

Description: The celestial sphere is an imaginary, hollow sphere apparently centered on Earth, of indefinitely large radius. The observable Universe can be mapped onto the surface of this sphere. Celestial objects appear to be attached to the inside of the celestial sphere, and the planets, Sun, and Moon appear to move slowly across it. It is used in spherical coordinate systems. The celestial sphere appears to turn once a day due to Earth’s rotation.

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Term and definition status: This term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".