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How to read a synastry chart: Introduction to relationship compatibility

Couple standing in a field

What is a synastry?

Synastry is a branch of astrology that examines how the positions of planets in one person's birth chart relate to those in another person's natal chart. It's a tool in Astrology for assessing compatibility in love and understanding the dynamics of a relationship by comparing key elements like the Sun, Moon, Venus, Mars, and more. Synastry helps identify areas of harmony, challenges, and attraction between individuals based on their astrological profiles.

How to read a synastry chart?

If you’re a beginner in Astrology, reading a synastry can be a challenging exercise. In this post we will cover a non-exhaustive list of things to look for when looking at a synastry for the first time. Once you read this introduction, you can read our other posts on synastry.

Step 1: Understanding the Natal Chart

The first thing you need to do before you dive into the synastry is to look at the respective charts. You need to have a good idea of what each person is bringing to the relationship, their needs, expectations, and vision. This is a primordial step for three reasons:

1) A seemingly "bad" synastry with difficult aspects might be exactly what you need based on your personal chart and sometimes people really miss out on this crucial point

2) You could have a wonderful synastry with let's say, Charles Manson. I'm not joking, I've seen it. You might just be compatible with a sociopath or, more commonly, someone who is just deeply wounded.

3) You want to be able to see if there are repeating patterns and mirroring happening in the relationship.

For example, if you're a Sun in Libra and your partner is an "incompatible" Sun sign, like let's say Capricorn, but they have in the 7th house, that's a resonance. This is something I put so much emphasis in and one of the first things I teach in my compatibility course.

If you're a Leo but with squares of Saturn, you might attract Capricorns and aficionados because you embody a similar energy.

Step 2: Do an overview of the relationship

I'm a big preacher of the big picture.

What is the most aspected planet?

What seems to be underwhelmed, not touching much?

Do you or your partner have a main planetary signature?

I've seen synastries where one's Moon does not receive any aspect from the partner and they will describe feeling neglected emotionally. It makes sense to me - their emotions and emotional needs aren't activated by the partner.

What are the aspects? Are they trines, conjunctions, squares? A trine relationship is an easy flow (which might or might not be what you need). A square relationship is one of struggle and growth and typically there is a lot of chemistry. A conjunction relationship is one of fusion, which can or not be a good thing, but there's definitely also an aspect of struggle (depending on the planets involved).

Step 3: The relationship planets

By order of importance, I would say: 1. Moon

2. Sun

3. Venus

4. Mars

5. Mercury

6. Jupiter

7. Saturn

Moon first for sure because it's the emotional connection, responsiveness and attunement, and as much as many people are in relationships that lack the above, they are simply not happy with it.

Another thing to consider is your own chart, for example, if you have a strong Moon element in your birth chart, showing how important it is for you to have a nurturing relationship filled with bonding and affection, you just would not function in a relationship that has Saturn square Moon in synastry because you could not overcome the sense of disconnection and loneliness.

Whereas if you're someone who's much less comfortable with emotional intimacy and is more so focused on achievements or longevity even if it lacks nurturance, then Moon might not be your first priority.

This is how you determine, based on your own personal chart, if the relationship is something that will work with your own personal needs.

For example, if you're a strong Mars and have high sexual needs, a relationship that lacks sexual spark would definitely be a turn-off for you, while many couples work perfectly fine without it. You might just prioritize chemistry.

Step 4: Look for double whammies

Look for what we call “double whammies” in the synastry chart. It’s a double aspect, for example, your Mars trine the person’s Pluto, and the person’s Mars conjunct your Pluto. Energies are going both ways, there’s a pattern here.

I look for what I call synchronicity. In your chart, you have your own patterns. Let’s say you have a square involving Sun and Neptune in your birth chart. You will often date people who have Sun/Neptune in aspect or a Pisces Sun. This is an indication that the relationship entering your life will be here to help you solve a pattern. It’s not mandatory to every lasting relationship, just a pattern to look out for.

Step 5: What about all those squares? 

Not everyone is cut out for the same type of relationship. Someone with an easy-flowing natal chart may run away from a dramatic relationship. Someone with challenging aspects in their own natal chart tend to be used to conflicts. We usually look for what we know and what we're familiar with, so you may be looking for someone who reproduces the conflictual energies you're used to. 

Not all squares are equal. Saturn square Moon in synastry for example is always a difficult aspect to have a synastry no matter how you put it. It might not be a dealbreaker but it is tough. Mars square Venus is entirely less difficult.

If there are hard aspects in the synastry from the outer planets, you do want to be mindful that this is a healthy relationship and not a toxic relationship. Especially if you find strong aspects of Pluto such as Pluto-Mars in the synastry chart, you want to be sure you're both in the relationship for the right reasons.

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