Astronomy Picture of the Day
    


Star Trails Over Oregon
<< Yesterday 9.09.2009 Tomorrow >>
Star Trails Over Oregon
Credit & Copyright: Joshua Bury
Explanation: As the Earth spins on its axis, the sky seems to rotate around us. This motion, called diurnal motion, produces the beautiful concentric trails traced by stars during time exposures. Partial-circle star trails are pictured above over Grants Pass, Oregon, USA last month. Near the middle of the circles is the North Celestial Pole (NCP), easily identified as the point in the sky at the center of all the star trail arcs. The star Polaris, commonly known as the North Star, made the very short bright circle near the NCP. About 12,000 years ago, the bright star Vega was the North Star, and in about 14,000 years, as the Earth's spin axis slowly continues to precess, Vega will become the North Star again.



January
February
March
April
May
June
July
August
September
October
November
December
 < September 2009  >
Mo Tu We Th Fr Sa Su

123456
78910111213
14151617181920
21222324252627
282930



Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: diurnal motion
Publications with words: diurnal motion
See also: