Astronomy:Colure

From HandWiki
Short description: Principal meridians of the celestial sphere
Orange = equinoctial colure
Blue = solstitial colure
G = equinoctial colure
H = solstitial colure

Colure, in astronomy, is either of the two principal meridians of the celestial sphere.

Equinoctial colure

The equinoctial colure is the meridian or great circle of the celestial sphere which passes through the celestial poles and the two equinoxes: the first point of Aries and the first point of Libra.

Solstitial colure

The solstitial colure is the meridian or great circle of the celestial sphere which passes through the poles and the two solstices: the first point of Cancer and the first point of Capricorn. There are several stars closely aligned with the solstitial colure: Pi Herculis, Delta Aurigae, and Theta Scorpii. This makes the solstitial colure point towards the North Celestial Pole and Polaris.

See also

References