Larisa
In short
Synastry is the astrological technique of comparing two people's birth charts, laying one over the other to see how their planets touch through aspects and fall into each other's houses. It goes far beyond Sun-sign compatibility, because it includes the Moon, rising sign, Venus, Mars and Saturn of both people. Synastry describes where two people meet easily and where they rub, never whether a relationship will last.
What is synastry?
Synastry is the comparison of two people’s birth charts, in which one chart is placed over the other to read how the planets of one person touch the planets, angles and houses of the other. It is the main technique astrologers use for relationships of every kind: romantic partners, friends, family members, colleagues.
Synastry rests on two kinds of contact:
- Inter-aspects: aspects between one person’s planets and the other’s, such as your Venus trine their Mars or your Saturn square their Moon. They describe how two people’s needs and drives meet.
- House overlays: where one person’s planets fall in the other’s houses. If your Sun falls in someone’s seventh house, they may experience you as a natural partner; in their tenth, as someone who affects their ambitions.
Simple zodiac compatibility compares only Sun signs, often by element. Synastry reaches much further: the Moon shows emotional rhythm, Venus and Mars attraction and desire, Mercury how two people talk, Saturn commitment and the sense of responsibility, and contacts to the ascendant describe the first, instinctive response to each other.
Synastry is different from the composite chart, which merges two charts into one by taking the midpoints of each pair of planets. Synastry shows what two people do to each other; the composite shows the relationship as a third thing with its own character.
Stars together: the history of synastry
The word combines the Greek syn, “together”, and astron, “star”: stars together. The idea is old. As early as the second century, Ptolemy judged the harmony of a marriage partly by how the Sun and Moon of the two charts related to each other, and medieval astrologers compared the charts of rulers, allies and spouses.
Modern synastry took shape in the twentieth century, when psychological astrology turned the focus from outcomes to dynamics. Instead of asking whether a match was fortunate, astrologers began asking what each person activates in the other, what feels easy and familiar, and what feels challenging and transforming. The comparison of Venus and Mars, of the two Moons and of Saturn contacts became the core of relationship astrology.
Today synastry is the technique behind most serious compatibility readings. Its best practitioners treat it as a map of a relationship’s themes, a description of a bond rather than a verdict on it. It is used just as much for friendships, parents and children, or business partners, where the same contacts describe trust, rivalry and mutual support.
Comparing two charts: where to start
Begin with the big three side by side. Write each person’s Sun, Moon and rising sign. Shared elements suggest ease; different ones suggest a need to learn each other’s language.
Compare the Moons. The Moon-to-Moon relationship is the compatibility felt most in daily life: how each person needs to be cared for when tired or upset, and whether the other naturally provides it.
Read Venus and Mars across the charts. One person’s Venus touching the other’s Mars is a classic signature of attraction. Venus with Venus describes shared taste and affection; Mars with Mars, how the two handle energy and conflict.
Look for Saturn contacts. Saturn touching the other person’s Sun, Moon or Venus often describes commitment and staying power, and sometimes heaviness or a sense of being judged. Many lasting relationships have strong Saturn ties.
Check the house overlays. Notice which houses each person’s personal planets fall in for the other. This shows which area of life the other person activates: home, work, creativity, beliefs.
No mind-reading. Synastry does not tell you what someone thinks, intends or will do. It describes a dynamic between two people, and both of them shape what it becomes.
In the Larisa app, the Compatibility tool compares two charts using your partner’s birth details.
Four synastry contacts, read through
Her Moon conjunct his Sun. A classic sign of mutual recognition: he feels seen and cared for, she feels warmed by his presence. Daily life together tends to feel natural. The work is not to fall into fixed roles, one always giving, one always receiving.
His Venus square her Mars. Strong attraction with friction built in. Desire and affection arrive at different paces: one wants closeness, the other wants action. Arguments may be frequent and passionate; so may reconciliation.
Saturn on a partner’s Moon. One person brings stability and seriousness, the other feels supported or, at times, held back. Over years this contact often describes loyalty. Talking openly about feelings keeps the Saturn person from becoming the critic.
Two charts with few contacts. Here the two sets of planets barely touch. The relationship may feel calm and easy but low in charge. Friendship or shared projects can thrive here, and in a partnership the bond grows through shared choices rather than through strong pull. Strong synastry is not the same as a good relationship, and quiet synastry is not the same as a weak one.
Larisa's approach
When I read synastry charts, I don't only ask “is there compatibility, will this become a relationship?” I try to understand which feelings two people trigger in each other, where the attraction comes from, the root of their conflicts, the way each of them attaches, and what the relationship teaches both sides. Rather than counting planetary aspects one by one, I read the whole story of the relationship; I take shadow, passion, fear, karma and transformation into account as much as love.
Frequently asked questions
What is the difference between synastry and zodiac compatibility?
Zodiac compatibility usually compares only two Sun signs, often by element. Synastry compares the whole of both charts: every planet, the angles and the houses. Two people with so-called incompatible Sun signs can show very strong synastry through their Moons, Venus and Mars.
Do I need both birth times for synastry?
For the full picture, yes. Without birth times you can still compare planets by sign and most aspects, but the rising signs and house overlays stay uncertain, and the Moon may be uncertain too. Planet-to-planet aspects are the most reliable part when times are missing.
What is the difference between synastry and a composite chart?
Synastry compares two separate charts to see how each person affects the other. A composite chart combines them into one chart, made from the midpoints of each pair of planets, and describes the relationship itself as a third entity. The two techniques answer different questions.
Can synastry tell me if my partner is the one?
No. Synastry describes the dynamic between two people: attraction, ease, friction and the lessons a bond brings. Whether a relationship lasts depends on communication, choices and work, which no chart comparison can decide.
Keep exploring
The readings offered by Larisa Tarot are provided for personal awareness, self-reflection and entertainment. They contain no certainty, no guarantee about the future and no promise of a particular outcome.