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right ascension
right ascension (RA) (symbol α) A coordinate on the celestial sphere, the equivalent of longitude on Earth. Right ascension is measured anticlockwise around the celestial equator, usually in hours, minutes, and seconds of sidereal time (although sometimes in degrees), starting from 0h at the vernal equinox. The 0h line of right ascension is the celestial equivalent of the Greenwich meridian on Earth. An hour of right ascension is equivalent to 15 degrees of arc, so that 24 h of RA is equivalent to 360°. Right ascension is an equatorial coordinate.
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"right ascension." A Dictionary of Astronomy. 1997. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. "right ascension." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O80-rightascension.html "right ascension." A Dictionary of Astronomy. 1997. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-rightascension.html |
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right ascension
right ascension in astronomy, one of the coordinates in the equatorial coordinate system . The right ascension of a celestial body is the angular distance measured eastward from the vernal equinox along the celestial equator to its intersection with the body's hour circle . |
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"right ascension." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. "right ascension." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1E1-rightasc.html "right ascension." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-rightasc.html |
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