← Encyclopedia of Astrology · lesson 6/235
Meridian
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What it is
Stand outside and draw an imaginary line across the sky from the north point of the horizon, straight up through the point directly overhead (the zenith), and down to the south point. That great circle is your meridian. It also runs on beneath your feet, through the point directly below (the nadir), so it cuts the sky into an eastern half and a western half.
Every place on Earth has its own meridian; it is the same idea as a line of geographical longitude, carried up onto the sky. The word comes from the Latin meridies, "midday": the Sun crosses the upper meridian at local noon, which is why we still say a.m. and p.m., ante and post meridiem.
What it gives a chart
As the sky turns through the day, each planet rises in the east, climbs to its highest point as it crosses the upper meridian — it culminates — sets in the west, and reaches its lowest point as it crosses the lower meridian.
The meridian cuts the ecliptic in two places:
- above the horizon, the Midheaven or Medium Coeli (MC), the culminating degree of the zodiac;
- below it, the Imum Coeli (IC), the lowest point.
With the horizon, which gives the Ascendant and Descendant, the meridian marks the four angles of the chart. On the chart wheel the MC is towards the top and the IC towards the bottom.
A common misunderstanding is that the Midheaven is the point straight overhead. It is not, except near the tropics: the MC is where the meridian meets the ecliptic, which in northern latitudes lies to the south of the zenith, sometimes far to the south.
How it is read
- Culmination. A planet close to the MC is at the top of the sky, the most visible place it can be. It is read as conspicuous in the life — often in reputation, vocation and how the person is seen in the world, the matters of the tenth house.
- The lower meridian. A planet near the IC is read through roots, home, family and private foundations, the matters of the fourth house.
- The axis. The MC–IC line is often read as the vertical axis of a life — public aims above, private ground below — as the horizon is read as the axis of self and others.
The meridian and house systems
In quadrant house systems such as Placidus, Koch, Regiomontanus and Porphyry, the MC is the cusp of the tenth house and the IC of the fourth. In whole-sign houses and equal houses it is not: the MC falls wherever it falls, often in the ninth or eleventh house, and is read as a point in its own right. This is one of the clearest differences between the systems, and worth knowing when two charts of the same birth disagree.
In the tradition
Hellenistic astrologers called the culminating place the mesouranēma, "mid-heaven", and read a planet there as active and prominent. Lilly gave the tenth house the same top score for strength as the first.
In a reading here
On the chart wheels here the Ascendant is fixed at the left, so the Midheaven stands in the upper half of the wheel, near the top, and the Imum Coeli opposite it near the bottom. It is exactly at the top only when it lies exactly 90° from the Ascendant.