+The **Celestial Sphere** is an imaginary sphere of infinite radius, concentric with [Earth](/wiki/earth), upon which all celestial objects appear projected. It serves as a fundamental model in [astronomy](/wiki/astronomy) and navigation, mapping the apparent positions of stars and planets.
+## See also
+- [Star](/wiki/star)
+- [Constellation](/wiki/constellation)
+- [Horizon](/wiki/horizon)
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