Sun-sign compatibility is the least informative layer of a relationship comparison. The angles — Ascendant, Descendant, Midheaven and IC — are calculated from the exact time and place of birth, and they show where another person actually lands in your life.
A partner's planet on your Ascendant is felt immediately and personally. On your Descendant it reads as the classic 'other' — attraction, contract, mirror. On the Midheaven it touches ambitions and public life; on the IC, home, family and private roots.
Remember that synastry is directional. Their Venus on your Ascendant is not the same experience as your Venus on theirs. That is why the workspace lets you swap the primary chart and read both directions.
No contact guarantees a happy relationship, and no difficult contact forbids one. Synastry describes the shape of the meeting; the people involved decide what they build inside it.
Start a synastry reading by checking how reliable both birth times are. If one time is uncertain by an hour, the angles and houses may shift entirely, and planet-to-planet contacts become the safer foundation.
Ascendant contacts often describe first impressions and physical ease. Someone's Moon on your Ascendant may make you feel instinctively understood; their Mars there can feel energising, provoking or both. These contacts are vivid early in a relationship and remain noticeable later.
Descendant contacts concern partnership itself. Their Sun on your Descendant may make them seem like the partner you were looking for — sometimes because they embody qualities you have not yet claimed. Such overlays invite projection, so a mature reading names that possibility.
Midheaven contacts link people through ambition, status and shared work. They are common in business partnerships and mentoring relationships. A partner's Saturn on your Midheaven can feel like a demanding teacher; their Jupiter there like a sponsor who opens doors.
IC contacts reach the private foundation: family patterns, home and the sense of being at rest. Their Venus on your IC may make shared domestic life feel natural; their Pluto there may unearth older family material that asks to be understood.
After the angles, read house overlays: which of your houses their planets fall into, and which of theirs your planets fall into. This is where the directional nature of synastry becomes concrete, because the same pair produces two different maps.
Finish with the aspect pattern between the personal planets — Sun, Moon, Mercury, Venus and Mars. Angles show where the meeting lands; planetary aspects show how it behaves day to day.