Composite Chart

A chart based on the combined birth data of two people – not to be confused with a Davison Relationship Chart. As with the latter, computers ease the task of discerning the main themes of the relationship.

Calculation

Midpoints are calculated based on taking the two natal charts of the people involved and halving the total sums – based on the smallest angle between them. For example, if one partner has the Moon at 13 degrees Taurus and the other at 27 degrees Aquarius, then the smallest angle between the two is 76 degrees. The composite Moon is located at the midpoint of 5 degrees Aries. The same method is used to calculate the position of all the other planets, the Moon's Nodes, and the MC and AC. The house cusps can be taken from a table of houses based on the positions of the composite MC and AC positions already calculated. An alternative way to calculate the Ascendant is to take the median time of birth at the place of birth – a method which can only be applied if the individuals were born at the same place.

Interpretation

The composite chart – as opposed to the Davison Relationship Chart – is a fictitious one which never actually existed in concrete reality. This doesn't prevent some astrologers from looking at planetary transits to it. For example, it is possible for composite Mercury to stand in opposition to the Sun although these two horoscope factors can otherwise never be separated by more than 28 degrees – see elongation.

The composite chart appears to reveal the energy present at the start of a relationship more than the deeper aspects of the relationship as represented in the Davison Relationship chart. The astrologer Mona Riegger is of the opinion that "the composite chart equates to seventh house themes, whereas the Davison Relationship chart is more a reflection of the eighth house. The composite describes the phase of discovery and the Davison Relationship chart that of stabilisation." And further: "A composite horoscope can give us insights into many different kinds of human interaction, whereas I would only use a Davison Relationship chart when looking at relationships in which there is a deeper sense of commitment."

The usual rules of interpretation apply. As with the Davison Relationship chart the composite chart can be approached in two ways: the first is to consider it as a whole, as standing for the partnership or relationship. But it can also help to reveal much about the individuals involved – in this case the Ascendant stands for the older person and the Descendent the younger one. This means that the Descendent is the Ascendant of the younger person, which in turn serves as a basis for interpreting the other houses in the horoscope (for example, the eighth house will be the second house etc).