Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2000 July 15
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Star Trails In Southern Skies
Credit: Photograph by David Malin
Copyright: Anglo-Australian Observatory

Explanation: As the Earth spins on its axis, the stars seem to rotate around us. This motion produces the beautiful concentric arcs traced out by the stars in this time exposure of the southern hemisphere night sky. In the foreground is the dome of the Anglo-Australian Telescope in central New South Wales, Australia. In the middle of the picture is the South Celestial Pole, the projection of Earth's axis of rotation into the southern sky. While the bright star Polaris lies conveniently close to the North Celestial Pole, no bright star similarly marks the pole in the south. Still, the South Celestial Pole is easily identified in the picture as the point in the sky at the center of all the star trail arcs.

Tomorrow's picture: The Ring

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/GSFC
& Michigan Tech. U.