celestial sphere

noun

Definition of celestial sphere

: an imaginary sphere of infinite radius against which the celestial bodies appear to be projected and of which the apparent dome of the visible sky forms half

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Recent Examples of celestial sphere from the Web

Together, the cameras will stare at a vertical strip of the celestial sphere stretching from the pole to the equator, proceeding to a new strip every 27 days.

— amina khan, latimes.com, "NASA is about to step up its planet-hunting game with the launch of TESS," 13 Apr. 2018
Pro-Plutonians recently suggested a new definition of a planet that would add the celestial sphere back to the solar system’s list of heavy hitters.

— jason daley, Smithsonian, "New Definition Would Make the Moon and Pluto Planets," 3 Mar. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'celestial sphere.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.