← Encyclopedia of Astrology · lesson 48/235
Midpoint
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What it is
A midpoint is the point on the zodiac exactly halfway between two planets or points. Take Venus at 10° Aries and Mars at 10° Gemini: the arc between them is 60°, and the halfway point is 10° Taurus. That spot is the Venus/Mars midpoint, written Venus/Mars. Nothing physical is there; it is a calculated point standing for the two planets combined.
Every pair has two midpoints, because a circle has two halfway points: the direct (or near) midpoint, in the middle of the shorter arc, and the point exactly opposite it, in the middle of the longer arc. Most practitioners treat both as sensitive. With ten planets and two angles, a chart holds sixty-six pairs — and so a great many midpoints, most of them quiet.
How it is worked out
The midpoint is the half-sum of the two longitudes, measured in absolute degrees from 0° Aries: add them and halve the total, then make sure the answer lies on the shorter arc (if it does not, add or subtract 180°). Venus at 10° Aries is 10°; Mars at 10° Gemini is 70°; (10 + 70) ÷ 2 = 40°, which is 10° Taurus.
How it is read
An empty midpoint is quiet. It comes alive when a third body — a planet, an angle such as the Ascendant or Midheaven, or a transiting planet — sits on it. That makes a midpoint picture, written as a little equation: Sun = Venus/Mars. It is read as one sentence: this planet, expressed through the meeting of those two. Someone with the Sun on their Venus/Mars midpoint might be read as a person whose sense of self is bound up with affection and desire.
The contact must be tight — usually within a degree or so, much closer than an ordinary orb. A planet several degrees away does not "sit" on the midpoint at all. Many schools also count a third body in hard aspect to the midpoint — 45°, 90°, 135° or 180° — which is easiest to see on a 90° dial, a rotating disc that folds the zodiac into quarters so that all those contacts line up.
In forecasting, a transit, solar arc or progression reaching a natal midpoint is read as setting off that pair together.
In the tradition
Halfway points appear here and there in older writing, but the technique as used today is modern. Alfred Witte and the Hamburg School, the founders of Uranian astrology in the early twentieth century, built their work on symmetrical points and planetary pictures; Reinhold Ebertin simplified it into cosmobiology, and his Combination of Stellar Influences (1940) remains the standard dictionary of midpoint meanings. Many traditional astrologers do not use midpoints at all, and many modern ones use only a handful — the Sun/Moon midpoint in particular. It is an advanced, optional tool; plenty of good chart reading is done without it.
Midpoints are also the basis of a relationship chart: a composite chart is built by taking the midpoint of each pair of matching planets in two birth charts.
In a reading here
Birth chart readings include a section of advanced chart techniques that lists midpoint pictures: any of the ten planets, the Ascendant or the Midheaven standing within 1° of the direct or opposite midpoint of two others.