Right ascension (abbreviated RA; symbol α, German: Rektaszension) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth.[1] When paired with declination, these astronomical coordinates specify the location of a point on the celestial sphere in the equatorial coordinate system.

Picture By Tfr000 (talk) 15:34, 15 June 2012 (UTC) - Own work, CC BY-SA 3.0 

For more information see Right ascension  on  Wikipedia

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