Synastry compares two natal charts. It explores how one person’s placements connect with another person’s placements, including aspects and house overlays. The most useful starting point is not ‘Are we meant to be?’ It is ‘What could help us understand the way we relate?’
Start with the people
Before comparing charts, name the relationship you are actually exploring. A friendship, creative partnership, and romantic relationship can raise different questions. Agree on what you want to discuss, and make sure the other person is comfortable sharing their birth details. Curiosity is most helpful when it has an invitation.
Choose a grounded question: how you make plans together, what happens after a disagreement, or what each person finds encouraging. A question about one real interaction produces a better conversation than asking a chart to deliver a permanent verdict about the relationship.
Read each chart on its own
A comparison makes more sense when neither chart disappears into the other. Begin by asking each person how they describe their own habits and needs. You might look at Moon themes for comfort, Mercury themes for communication, or Venus themes for preferences, while remembering that the person can disagree with an interpretation.
Suppose one person likes to talk through a plan immediately and the other likes time to consider it. That difference can be described without deciding who is difficult. The chart offers a vocabulary; the actual preference needs to come from the person. Do not use their placements to answer on their behalf.
Treat aspects as conversation prompts
A synastry aspect connects a planet in one chart with a planet in the other. Read the two themes first, then consider the aspect’s style. A connection between Mercury and the Moon might lead to questions about how conversation meets emotional needs. The names of the planets do not tell you whether those needs are being met.
For example, ask: ‘When I try to solve the problem quickly, do you feel supported or interrupted?’ Both answers are possible. A harmonious aspect is not proof of kindness, and a challenging aspect is not proof that a relationship cannot work. What people do with each other carries more weight than the label.
Understand what an overlay adds
A house overlay places one person’s planet in an area of the other person’s chart. It adds a setting to the conversation. An overlay associated with the fourth house might invite reflection on home, familiarity, or private life. It does not establish that someone must move in with you or belong in your future.
Accurate birth times are especially relevant when interpreting houses. If those times are missing or uncertain, keep the limitation visible. You can still explore some planetary connections, but a detailed story about the house placement may rest on information you do not actually have.
End with something you can try
Choose a small agreement that follows from the conversation. You might give each other a day to think before confirming plans, ask before offering advice, or distinguish between wanting company and wanting a solution. The agreement should be understandable even without knowing anything about astrology.
Return to it after a week or two. Did it make the interaction clearer? Did the interpretation overlook something important? Let experience revise the reading. If the relationship involves disrespect or harm, do not explain it away as cosmic intensity. Your boundaries do not need permission from a chart, and a connection does not require you to stay.
Keep what opens a useful question.
Let your experience have the last word.