celestial sphere

noun

1. the imaginary spherical shell formed by the sky, usually represented as an infinite sphere, the center of which is a given observer's position.

celestial sphere

noun

1. an imaginary sphere of infinitely large radius enclosing the universe so that all celestial bodies appear to be projected onto its surface

celestial sphere

1. An imaginary sphere with Earth at its center. The stars, planets, Sun, Moon, and other celestial bodies appear to be located on this sphere, and the sphere appears to rotate around the Earth's extended axis once every 24 hours, carrying the celestial bodies with it overhead and giving them their diurnal motions. The celestial sphere is essentially a spherical map of the sky that provides the basis for the coordinate systems used in celestial navigation and in specifying the positions and motions of celestial objects.
2. See more at altazimuth coordinate system

Word History and Origins

Origin of celestial sphere¹

First recorded in 1875–80

Example Sentences

But from a terrestrial perspective, the celestial sphere appears essentially unchanging.

From Scientific American

This pairing hums with a soft energy, attuned perhaps to the same celestial spheres that Gouverneur hoped to crack open.

From Washington Post

But there’s no need to be perfectly versed in every detail of the celestial sphere.

From New York Times

In his only surviving work, Hipparchus criticized earlier astronomical writers for not caring about numerical accuracy in their visions of orbits and celestial spheres.

From Scientific American

Their model of the universe involved the "celestial spheres" creating a kind of harmony as they moved in circles dictated by the same arithmetical relationships as musical harmonies.

From Literature