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.
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Some articles on celestial sphere:
... The Celestial Sphere is a large scale oratorio for chorus and orchestra by Charles Wuorinen, commissioned by Augustana College (Rock Island, Illinois) for the 100th anniversary of the ... Wuorinen's full title is The Celestial Sphere / An Oratorio / For Mixed Chorus / And Orchestra / Containing I ...
... All the stars appear to lie on the imaginary Celestial sphere ... Because of the rotation of the Earth, the Celestial Sphere appears to rotate around an axis passing through the North and South poles of the Earth ... This axis intersects the Celestial Sphere at the North and South Celestial poles, which appear to the observer to lie directly above due North and South respectively on the horizon ...
... The navigational or PZX triangle is a term used in Astro-Navigation, or Celestial Navigation, and its solution can give you your position anywhere (more or less) on the globe ... The sky is described as a Celestial Sphere with a North and South Pole corresponding to our own North and South Pole ... Star' lies (more or less) at the North Pole of the Celestial Sphere ...
... provide four star charts, covering different portions of the celestial sphere ... The other two cover the equatorial region of the celestial sphere, from the declination of 30° south to 30° north ... projections, one for the eastern hemisphere of the celestial sphere and one for the western hemisphere ...
... A celestial sphere can also refer to a physical model of the celestial sphere or celestial globe ... Such globes map the constellations on the outside of a sphere, resulting in a mirror image of the constellations as seen from Earth ...
Famous quotes containing the words sphere and/or celestial:
“A knowledge of the Globe and its various inhabitants, however slight ... has a kindred effect with that of seeing them as travellers, which never fails, in uncorrupted minds, to weaken local prejudices, and enlarge the sphere of benevolent feelings.”
—James Madison (1751–1836)
“Such is always the pursuit of knowledge. The celestial fruits, the golden apples of the Hesperides, are ever guarded by a hundred-headed dragon which never sleeps, so that it is an Herculean labor to pluck them.”
—Henry David Thoreau (1817–1862)