Composite Chart

How to create a midpoint chart that represents the relationship itself.

A composite chart is a single chart for a relationship as its own entity. It is built from the midpoints between two people’s planetary positions, so it describes the partnership rather than either person. That makes it a way into the nature and direction of the relationship.

Access

Open the composite chart from Compatibility in the sidebar.

Choose the base person under Birth Details in the sidebar
Select “Composite” under Compatibility
Choose the second person with Select Person B at the top of the chart (the same dialog used for synastry), from your saved birth details

You can also press the chart title on any chart screen and switch to it from there.

How it is calculated

HOSHIDOU’s composite uses the midpoint method. Each composite planet sits at the midpoint of the two people’s longitudes for that body. For example, if the base person’s Sun is at 10° Aries and the second person’s Sun is at 20° Aries, the composite Sun lands at 15° Aries. The same calculation is applied to every planet and sensitive point, and the results are drawn on one wheel.

The midpoint is taken on the shorter arc between the two positions. For houses, the midpoint of the two people’s ASCs becomes the composite ASC, and the houses are equal houses of 30° counted from it. The house system setting does not apply here.

The Davison composite, one chart cast for the midpoint in time and space between the two births, is not supported.

How it differs from synastry

Both synastry and the composite chart look at a relationship, from different angles.

Synastry overlays two natal charts. It shows how one person’s planets touch the other’s houses and aspects, the way the two interact.
Composite merges the two charts into one. It treats the relationship as a third entity and asks what that relationship is like.

Synastry shows the movement between two people; the composite describes the relationship as a whole. Looking at both gives you a fuller picture.

Reading the chart

You can read a composite chart the way you read a natal chart. Signs, houses, and aspects carry their usual meanings, and they describe the relationship rather than one person.

Composite wheel built from the pair's midpoints

Composite Sun: the central theme and purpose of the relationship
Composite Moon: the emotional tone and shared needs when the two people are together
Composite aspects: how the energies of the relationship fit together, and where adjusting may be needed

Houses show which areas of life the relationship tends to show up in.

You can also use Export chart to export a composite chart as an image or PDF. See Chart export for the available formats.

A reading example

Suppose the composite Sun is in the 7th house, in Libra. The 7th house is the area of partnership, so this placement suggests a relationship in which the partnership itself is the central theme. Libra values balance and fairness. You read this as a quality that tends to appear when the two people are together, not as the tendency of either one.

Synastry: overlaying two charts, the counterpart to the composite.
Compatibility Score: six category numbers worked out from the two people’s angles.