Colure

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 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 of the celestial sphere which passes through the poles and the two solstices: the first point of Cancer and the first point of Capricorn.

References

• John Brian Harley, David Woodward. The History of cartography, Volume 2. Oxford University Press US, 1987. ISBN 9780226316352. Page 28.
• Geminus, James Evans, J. L. Berggren. Geminos's Introduction to the phenomena: a translation and study of a Hellenistic survey of astronomy. Princeton University Press, 2006. ISBN 9780691123394. Page 130.

See also

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