The relationship has a chart of its own.

The math of a composite chart fits in one sentence: every planet is placed at the midpoint of its two natal positions. The composite Sun is the point on the zodiac halfway between your Sun and your partner's; the same goes for the Moon, Venus, Saturn and the rest. What comes out is not an average of two personalities but a genuinely new chart.

A concrete example: your Sun sits at 10 degrees Aries, your partner's at 10 degrees Gemini. The composite Sun lands at 10 degrees Taurus — a sign neither of you has anywhere in your chart. That is exactly why composite charts surprise people: the chart does not resemble either of you. It resembles the third thing that only exists when you are together.

One note for the reader who has heard the term: an alternative technique called the Davison chart uses the real midpoint in time and space instead — it computes the actual sky for the moment halfway between your two births, seen from the point halfway between your birthplaces. Baby Astro computes the midpoint composite, the more widely used form.

Synastry lays two charts on top of each other and asks what you do to each other: does her Saturn sit on your Moon, does your Mars set off his Venus. The composite builds a single chart and asks something else entirely: what is this relationship, on its own, as a thing in the world?

The two questions do not have to give the same answer — and that is where it gets interesting. Two people with soft, easy synastry can form a composite with a heavy Saturn: comfortable side by side, hesitant the moment commitment comes up. The reverse happens too — a friction-filled synastry under a rock-solid composite, the couple everyone wonders about that somehow never falls apart. The composite is the chart that explains the couples who puzzle their friends.

So a composite is read alongside synastry, never instead of it. The usual order: synastry first, to see what each of you touches in the other; then the composite, to see what kind of shared entity those touches add up to. Baby Astro generates both from the same birth data, so you can move between the two readings freely.

A composite needs both people's birth data — date and city at minimum, times for the full chart. Without birth times, the planetary midpoints still compute: composite Sun, Venus, Mars and Saturn come out reliably, with only the fast-moving Moon picking up some uncertainty. What you lose are the composite Ascendant, the Midheaven and all twelve houses.

Houses ask for one more decision. Composite planets are location-independent, but placing them into houses requires choosing a reference location, and the convention is to use the place where the couple lives. That sounds odd, yet it is an honest part of the technique: the same relationship distributes into different houses in Istanbul than in Berlin. The composite 7th house — how the relationship commits — is therefore a reading that depends on both the birth times and the chosen place.

Baby Astro builds what the data supports and does not invent the rest: with times missing, it still shows the chart and says plainly which sections stay uncertain. And one thing stated up front — a composite is not a referee ruling on whether the relationship will work. It describes what you gather around, what the bond gets hungry for and where it grows heavy; the decision always belongs to the two of you.