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The celestial sphere is a geometric model that treats the sky as if objects were projected onto a vast sphere surrounding the observer.
supportedThe celestial sphere is a geometric model that treats the sky as if objects were projected onto a vast sphere surrounding the observer. Coordinate systems let observers translate a catalog position into a direction that a telescope mount can track.
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The celestial sphere is a geometric model that treats the sky as if objects were projected onto a vast sphere surrounding the observer.
supportedEarth's rotation makes the celestial sphere appear to rotate once per sidereal day.
supportedLong-exposure star trails circle the celestial poles, while repeated positional measurements show predictable daily and annual motions.