Synastry

Synastry is the comparison of two natal charts to examine how the people they describe tend to interact — the points of attraction, friction, and resonance between them.

Synastry compares two birth charts by overlaying them and noting the aspects formed between one person's planets and the other's. A person's Venus conjunct another person's Mars, for example, is read as a strong mutual attraction signature; one person's Saturn opposite another's Sun is read as a relationship in which one person's structuring or limiting function tends to land on the other's core identity. In addition to inter-chart aspects, synastry examines house overlays — which of person A's planets fall into which of person B's houses, and vice versa. Person A's Sun falling in person B's 7th house, for instance, is often read as person A occupying a 'partner' position in person B's life. Sign and element compatibilities are also commonly considered, though these are the most simplistic and most prone to overreading. A composite chart — a separate technique often paired with synastry — generates a single 'relationship chart' by taking the midpoints between the two people's planets. The composite chart is read as describing the relationship as its own entity, distinct from either individual. Honest synastry practice resists the temptation to declare relationships 'compatible' or 'incompatible.' What charts show is patterns of interaction — what tends to come easily, where friction tends to recur, what dynamics will need to be worked with consciously. Compatibility is a function of two people's willingness to do that work, not of their birth charts.

Not: Synastry is not a compatibility test. No chart comparison can determine whether two people 'should' be together, whether a relationship will last, or whether one partner is 'right' for the other. The patterns synastry describes are starting points for reflection, not verdicts on viability.

Synastry techniques have no empirical validation as predictors of relationship outcomes. Decades of research on astrological compatibility — most notably studies of marriage and divorce rates by sun sign — have found no measurable effects. The value of synastry is reflective: it can offer language for noticing patterns that two people are already experiencing, not predictive insight into whether to enter or leave a relationship.