Celestial Sphere

In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the observer. All objects in the observer's sky can be thought of as projected upon the inside surface of the celestial sphere, as if it were the underside of a dome or a hemispherical screen. The celestial sphere is a practical tool for spherical astronomy, allowing observers to plot positions of objects in the sky when their distances are unknown or unimportant.

Read more about Celestial Sphere:  Introduction, Celestial Coordinate Systems, History, Star Globe

Famous quotes containing the words celestial and/or sphere:

    We have reason to be grateful for celestial phenomena, for they chiefly answer to the ideal in man.
    Henry David Thoreau (1817–1862)

    Don’t feel guilty if you don’t immediately love your stepchildren as you do your own, or as much as you think you should. Everyone needs time to adjust to the new family, adults included. There is no such thing as an “instant parent.”
    Actually, no concrete object lies outside of the poetic sphere as long as the poet knows how to use the object properly.
    Johann Wolfgang Von Goethe (1749–1832)