circle of right ascension

circle of right ascension

[′sər·kəl əv ′rīt ə′sen·shən] (astronomy) hour circle

hour circle

Any great circle joining the celestial poles and passing through a point on the celestial sphere. All celestial bodies are positioned on particular hour circles. Unlike celestial meridians, which remain fixed with respect to the earth, hour circles move with the celestial sphere as it rotates about the earth. Also called a circle of declination or a circle of right ascension.