Astronomy:Colure

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

• Celestial coordinate system
• Ecliptic
• Celestial sphere
• Right ascension
• Equinox
• Solstice

References

• Harley, John Brian; Woodward, David (1987). Cartography in the Traditional Islamic and South Asian Societies. The History of cartography. 2:1. University of Chicago Press. p. 28. ISBN 978-0-226-31635-2. OCLC 13456456. 
• Geminus; Evans, James; Berggren, J. L. (2006). Geminos's Introduction to the phenomena: a translation and study of a Hellenistic survey of astronomy. Princeton University Press. p. 130. ISBN 978-0-691-12339-4. OCLC 70232402. 
• Ovason, David (1999). The Secret Architecture of our Nation's Capital. Harper Collins. p. 98. ISBN 978-006095368-3. OCLC 50409366. https://archive.org/details/secretarchitectu00ovas/page/98. 
• Kaler, Jim. "Pi Aurigae." Pi Aurigae. N.p. 22 Feb. 2008. Web.