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:
“When the spirit brings light into our minds, it dispels darkness. We see it, as we do that of the sun at noon, and need not the twilight of reason to show it us. This light from heaven is strong, clear, and pure carries its own demonstration with it; and we may as naturally take a glow-worm to assist us to discover the sun, as to examine the celestial ray by our dim candle, reason.”
—John Locke (1632–1704)
“Prayer is the fair and radiant daughter of all the human virtues, the arch connecting heaven and earth, the sweet companion that is alike the lion and the dove; and prayer will give you the key of heaven. As pure and as bold as innocence, as strong as all things are that are entire and single, this fair and invincible queen rests on the material world; she has taken possession of it; for, like the sun, she casts about it a sphere of light.”
—Honoré De Balzac (1799–1850)