# Synastry

> Synastry compares two birth charts to read how two people interact. How the aspects between them work and what astrologers look for.

- Page: https://novaoracles.com/glossary/synastry
- Language: en

Synastry is the practice of reading two natal charts against each other to see how two people interact. It lays one chart over the other and looks at the aspects between them: your Venus to their Mars, your Moon to their Sun, and so on. A trine or sextile between the two tends to feel easy, a square or opposition more charged, and the mix is what gives a connection its character.

Synastry is the astrology of two. Instead of reading one chart on its own, you lay two natal charts side by side and study how they touch, which of your planets reach out to which of another person's. It is the technique most people mean when they ask whether two charts are compatible.

## Cross-measuring two charts: aspects and house overlays

Both charts are ordinary birth charts, computed from two real births. Synastry adds no new astronomy; it cross-measures the angles between them. You look at the [aspects](https://novaoracles.com/glossary/aspect) one person's planets make to the other's, so your Venus to their Mars, your Moon to their Sun, and note which are close and which are wide. You also see which of their houses your planets fall into, which shows where you tend to activate their life. Those two layers, the planet-to-planet aspects and the house overlays, make up a synastry reading.

## Venus, Mars, Sun, Moon and Saturn contacts

Tradition assigns meaning to the pairings. Venus and Mars contacts are read as attraction, Sun and Moon contacts as a feeling of home, Saturn contacts as commitment and weight, and the outer planets as fascination or upheaval. Soft aspects between two charts are read as ease and flow, hard ones as friction that can be either exciting or wearing. No single contact is taken to make or break a match; the pattern across the whole comparison is what counts.

## One person's Venus on the other's Sun

Suppose one person's Venus sits right on the other's Sun. That contact is read as warm and affectionate, the Venus person delighting in the Sun person and the Sun person feeling appreciated. Add a Mars square between them and you get attraction with an edge, a spark that can tip into friction, which is why readers weigh the whole set of contacts rather than any one.

## Synastry, composite and sun-sign matching

Synastry is not the same as a [composite](https://novaoracles.com/glossary/composite) chart; synastry compares two separate charts, while a composite merges them into one. It is also far more than sun-sign compatibility, since it uses every planet and point in both charts, not just the two Suns. And a difficult aspect or two does not doom a relationship, because context decides how a contact actually plays out.

## Two charts compared side by side

The NovaOracles [compatibility tool](https://novaoracles.com/tools/compatibility) compares two charts and finds the aspects between them, the [compatibility guide](https://novaoracles.com/guides/compatibility) explains how to weigh them, and [compatibility and synastry explained](https://novaoracles.com/blog/compatibility-and-synastry-explained) goes deeper.

## FAQ

### What is synastry in astrology?

The technique of comparing two birth charts to see how two people connect. It looks at the aspects between one person's planets and the other's, and at whose houses each activates.

### What is the difference between synastry and a composite chart?

Synastry keeps two separate charts and studies the contacts between them. A composite merges the two into one chart that stands for the relationship itself.

### What are the most important aspects in synastry?

Contacts between the Sun, Moon, Venus and Mars carry the most weight, read for warmth, ease and attraction. Saturn contacts add commitment and staying power.