Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
celestial meridian
References
Images
Celestial coordinates seen by an observer in mid-northern latitudes. His celestial meridian is a great circle passing through his zenith and the poles. His astronomical horizon meets the celestial sphere at infinity.
Britannica AI Icon

celestial meridian

astronomy
Written by
The Information Architects of Encyclopaedia Britannica

The Information Architects maintain a master list of the topics included in the corpus of  Encyclopædia Britannica, and create and manage the relationships between them.
The Information Architects of Encyclopaedia Britannica
Last updated

Quick Summary

Celestial coordinates seen by an observer in mid-northern latitudes. His celestial meridian is a great circle passing through his zenith and the poles. His astronomical horizon meets the celestial sphere at infinity.
Celestial coordinates seen by an observer in mid-northern latitudes. His celestial meridian is a great circle passing through his zenith and the poles. His astronomical horizon meets the celestial sphere at infinity.

A celestial meridian is a great circle on the celestial sphere that passes through the celestial poles and the zenith. This imaginary line is crucial in astronomy for establishing celestial coordinate systems, similar to how longitude lines are used on Earth.123

The concept is related to the celestial equator, which is the great circle midway between the celestial poles. Historically, the Greenwich meridian served as the prime meridian (0° longitude) on Earth, aiding in navigation and the standardization of astronomical maps. While the Earth's prime meridian has been updated, the principle of using meridians remains fundamental in astronomy for mapping and understanding the positions of celestial objects.423

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
4 Britannica Sources
  1. celestial meridian
  2. Greenwich meridian
  3. celestial equator
  4. astronomical map - The equatorial system

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.