Composite Chart
Type the birth details of two people. Each planet of the composite sits halfway between theirs.
What a composite chart is
Synastry compares two people. A composite chart does something different: it merges them into a single chart and reads the relationship as if it were a third person with its own Sun, Moon and planets. The composite Sun is read as the purpose of the bond, the composite Moon as its emotional climate.
Each composite position is the midpoint of the two natal positions, taken along the shorter arc. If one Sun is at 10 degrees Aries and the other at 20 degrees Gemini, the composite Sun sits at 15 degrees Taurus. Taking the shorter arc matters; the far midpoint would land in the opposite sign.
With both birth times, we also give the midpoint of the two Midheavens. Houses are left out, because a composite has no single time and place of its own, and the shortcuts used to invent them disagree.
Reading the composite Sun
| Composite Sun in | The relationship is about |
|---|---|
| Aries | Doing things first, together |
| Taurus | Building comfort and security |
| Gemini | Talking, learning, staying curious |
| Cancer | Making a home and a family |
| Leo | Celebrating and creating |
| Virgo | Working well together, daily care |
| Libra | Partnership itself, balance |
| Scorpio | Depth, loyalty, transformation |
| Sagittarius | Growth, travel, shared beliefs |
| Capricorn | Long-term goals and standing |
| Aquarius | Friendship and freedom |
| Pisces | Compassion, art, spiritual ties |
Worked examples
- 1990-03-05 New York and 1985-11-29 London: the composite Sun is at
25°54′ Capricorn - The composite Moon of the same pair:
00°43′ Cancer - 1983-05-25 Los Angeles and 1988-07-07 Tokyo: the Midheaven midpoint is
24°11′ Cancer
How this is calculated
Composite position = midpoint of the two natal longitudes along the shorter arc, for Sun to Pluto and the north node; Midheaven midpoint when both times are known. Aspects inside the composite use the site's aspect table. No composite houses.