Meridian

Definition

The meridian is the celestial great circle that passes through the north and south celestial poles, the observer’s zenith, and the nadir below. It divides the sky into eastern and western halves. Where the local meridian intersects the ecliptic, it establishes the Midheaven above and the Imum Coeli below. Because it is calculated for a particular time and location, the meridian is fundamental to chart orientation.

Astrological Meaning

In astrology, the meridian forms the vertical axis commonly called the MC–IC axis. The Midheaven side is associated with public life, reputation, vocation, visibility, and one’s contribution to the wider world. The Imum Coeli side concerns roots, home, ancestry, privacy, and inner foundations. Planets close to either end of this axis are often considered especially prominent. The meridian itself is an astronomical reference rather than a planet or interpretive influence.

Why It Matters

Understanding the meridian helps distinguish chart angles from house cusps. In many quadrant house systems, the Midheaven marks the tenth-house cusp and the Imum Coeli marks the fourth-house cusp. In whole-sign or equal-house charts, however, these points may fall within other houses. This distinction allows astrologers to interpret angular emphasis, houses, and public or private themes without treating them as interchangeable. Accurate birth time and location are important because even modest changes can shift the meridian and its contacts with planets.

Related Encyclopedia Entries

• Traditional Astrology
• Astrological Terminology
• Natal Chart
• Midheaven
• Imum Coeli