Synastry and composite charts

Two methods, two questions

Synastry and composite charts answer different questions. Synastry asks what happens between these two people. A composite asks what kind of entity appears when they come together. The two complement each other but do not replace each other.

One thing first: neither method produces a score. Astrological contacts describe themes and dynamics, not chances of success. A relationship with many tense aspects can be durable, and one with many harmonious contacts can become dull.

Synastry

Synastry compares two complete charts and looks at the aspects between them. Contacts to the Sun, Moon, Venus, Mars and the angles tend to stand out, because they touch direction, emotional needs and attraction.

A difficult aspect does not predict failure; it describes a theme that needs attention. Saturn contacts, for instance, are considered demanding, yet they are often exactly what gives a connection durability.

It is also revealing which houses of one chart the other person’s planets fall into. If one person’s Moon lands in the other’s fourth house, that touches themes of home and belonging regardless of the other aspects.

Composite

A composite uses mathematical midpoints between the planets of both charts. It is read as a symbol for the relationship as a system in its own right: what atmosphere appears when the two come together, and what does the connection revolve around?

A composite does not describe either person. It can show themes that neither brings alone and that only arise between them. A composite Sun in the eleventh house, for example, suggests a connection built around a shared circle and shared goals.

Because a composite is averaged from both charts, any uncertainty in the birth data carries over twice. Without reliable times, composite houses should be treated with care.

Data quality

Without accurate times, contacts between planets remain usable but houses and angles can become uncertain. For a composite the same caution applies in a stronger form.

If one of the two birth times is unreliable, concentrate on aspects between slower factors and deliberately leave house statements out. An honest gap is far more useful than invented precision.

Responsibility

Respect, communication, safety and consent cannot be derived from a chart. Astrological patterns must never be used to explain away control, boundary violations or harmful behaviour.

A relationship chart is also not a tool for judging someone who knows nothing about it. It works best when both people know it and use it as a starting point for conversation rather than as a verdict.

Try it with your own chart

Calculate your free chart first, then use this reading order as a guide.