Synastry

Comparing charts is not a compatibility score

Synastry is the technique of laying one natal chart over another: where one person's planets fall in the other's houses, and which aspects form between the two charts. People searching 'compare birth charts' usually want this, not two Sun signs in a grid.

Sun-sign compatibility pages are a starting cartoon. Moon, Venus, Mars, rising signs, seventh houses, and the aspects between charts carry more of the relational information. Even then, a chart cannot tell you whether two people should stay.

What a useful synastry reading asks

How does each person give and receive care? What happens under conflict? Where is there heat, and where is there rest? Which qualities get projected onto the other person? Those questions need both charts and both people's actual behaviour.

No aspect decides a relationship. Consent, shared values, and repair matter more than a trine.

What Astro Codes offers now

The calculator currently builds individual natal charts. This guide exists so synastry is explained honestly, including the limit: we do not yet compare two charts in-app. Get each person's natal chart right first. That is the input synastry requires anyway.

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