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.
"right ascension." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 21, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/right-ascension
"right ascension." The Columbia Encyclopedia, 6th ed.. . Retrieved February 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/right-ascension