TWO CHARTS TOGETHER
Synastry:
how two charts are compared
Synastry is the comparison of two birth charts. It looks at the angles between one person's planets and the other's, and at which houses each person's planets fall into in the other's chart, to describe how two people tend to affect each other.
What synastry actually measures
Two things. First, cross-aspects: the angle between your Moon and their Mars, your Venus and their Saturn, and so on. Second, house overlays: which area of your life their planets land in, and vice versa.
A contact is only worth reading if it is close. Within a degree or two, an aspect is something both people can usually name. At eight degrees it is atmosphere at best, and reading it loudly is how synastry earns its bad reputation.
The contacts that carry the most weight
Not all pairs of planets are equally informative about a relationship.
- Moon to Moon, or Moon to anything personal — whether the two of you find each other restful.
- Sun to Moon — a classic mutual-recognition contact, common in long partnerships and in close parent-child bonds.
- Venus to Mars — attraction and pace; in non-romantic pairs it reads as easy enjoyment of each other's company.
- Saturn to a personal planet — duty, weight, and staying power, sometimes experienced as pressure.
- Ascendant contacts — whether you simply like the way the other person shows up.
What a compatibility score can and cannot say
A number is a summary of how many close, weighty contacts two charts make, and of whether those contacts are flowing or frictional. That is genuinely useful information — and it is not a verdict on a relationship.
Harmonious charts can be comfortable and inert. Frictional charts can be the ones that hold people's attention for decades. Any tool that tells you a relationship is doomed from two dates of birth is overreaching, and any score worth trusting should be able to show you the specific contacts it counted.
Synastry is not only for romance
The same technique applies to a parent and child, two siblings, a grandparent and grandchild, or co-parents. The contacts mean different things in different relationships: Venus-Mars between adults is attraction; between a parent and a small child it is simple delight in each other.
Kinastry reads every pair in a household with the relationship and the ages in mind, and never writes romantic language for mixed-age or family pairs. A child's chart is always read as a child's chart.
Composite charts, briefly
Synastry compares two charts. A composite chart averages them into a single third chart, read as the relationship itself. Both are legitimate; synastry is more concrete about who does what to whom, which is usually what people actually want to know.
COMMON QUESTIONS
Questions people ask
- What is a synastry chart?
- A synastry chart is a comparison of two birth charts. It measures the angles between one person's planets and the other's, and shows which of each person's houses the other's planets fall into, to describe how the two tend to affect each other.
- How accurate is astrological compatibility?
- Synastry is a description of tendencies, not a prediction. Close contacts between the Moon, Sun, Venus, Mars, and the Ascendant genuinely describe recognisable dynamics, but no chart comparison can decide whether a relationship will last.
- Can synastry be used for family, not just couples?
- Yes. The same contacts apply to parents and children, siblings, and grandparents, and are simply read differently: the same aspect means attraction between adults and easy delight between a parent and a young child.
KEEP READING
Family astrology
Family astrology reads a household as a set of related charts rather than one chart at a time. It looks for signs and placements that repeat across generations, for the contacts between each pair, and for how the same day in the sky lands differently on each person in the same home.
What a birth chart is
A birth chart — also called a natal chart — is a map of the sky at the exact moment and place a person was born. It records where the Sun, Moon, and planets stood, which sign was rising on the eastern horizon, and how the sky was divided into twelve houses from that spot on Earth.
Transits and horoscopes
A transit is a planet's current position touching a placement in your birth chart. Today's sky is identical for everyone, but it lands on a different part of each person's chart, which is why a genuine horoscope has to be built from your own birth details rather than your Sun sign alone.
Your own family's charts, calculated exactly and read gently.
Chart your family