Composite and Davison Charts

If synastry compares two charts side by side, a composite chart blends them into a single chart that stands for the relationship itself. It asks: when we are together, what are we as a pair?

The composite chart

It is built by finding the midpoint between each pair of matching planets. If your Sun is at 10° Aries and the other person’s Sun is at 20° Libra, the midpoint of those two positions, measured along the shorter arc of the zodiac, becomes the Sun in the composite chart (here 15° Capricorn). Do the same for every planet and you get a new chart that belongs to neither person. The Midheaven is blended in the same way, and the Ascendant and houses are then worked out from it for the average of the two birth latitudes. You read it like an ordinary birth chart, looking at the Sun, Moon, Ascendant, and aspects to see the purpose, mood, and lessons of the relationship.

The Davison chart

The other method finds the midpoint in time and in place between the two births, then casts a real chart for that date, time, and location. A Davison chart therefore shows an actual sky, whereas the composite is a mathematical average. Its planets sit in positions that really existed, and it has its own Ascendant and houses.

A group of three to five

Both methods also work for a group, such as business partners, a team or a family. For a composite, each planet goes to the average of everyone’s positions round the circle, and the Midheaven is averaged the same way before the houses are worked out. For a Davison chart, the moment is the average of the birth moments and the place the centre of the birthplaces. When a planet is spread widely across the group, say three Suns about 120° apart, the average points nowhere clear, so read the planets the group clearly shares first. The app then reads a group three ways: whose own Sun, Moon, Ascendant or MC sits near the composite’s, five group themes, and the pairs with the tightest supportive or challenging contact.

In the app

Pick two charts (members can add up to five people) and switch between the two methods. A planet without a clear midpoint in a group is drawn as a hollow circle and listed under the wheel. Each comes with a wheel, tables of positions, houses and aspects, and a balance summary. Under the wheel, house overlay tables show which of the chart’s houses each person’s planets fall in, and which of each person’s houses the chart’s planets fall in (every birth time is needed). The composite is not the sky at any real moment, so nothing in it is retrograde. They are two views of the same bond: some prefer the composite as the relationship’s own identity, others the Davison because it is a real chart.

Worth remembering

Neither chart says whether a relationship will succeed or fail. Use them as a mirror for both people, to explore what you are building together and where you might like to grow.