Astrological compatibility
When I speak of compatibility, I mean the emotional meeting between your way of expressing affection and desire and your partner’s: the pleasure, the ease, the enthusiasm or the unease that shows up when you share time and space. Some company makes us want to stay a little longer; other company stirs discomfort or makes closeness hard.
Affinity can awaken the wish to do things together and open a place for love. What the couple actually builds calls for a wider view, that of planetary relationships and the houses. In that reading, each person’s experience helps tell the attraction they feel apart from the commitments they want to take on.
Synastry compares the two people’s birth charts. To explore that first approach, I use five criteria. As you follow them, notice whose position is being compared in each case.
Affinity between the elements
Traditional astrology speaks of four elements: fire, earth, air and water. In the system I use, they go by the following names:
Name in this system: Hydrogen; Traditional name: Fire; Signs: Aries, Leo and Sagittarius.
Name in this system: Silicates; Traditional name: Earth; Signs: Taurus, Virgo and Capricorn.
Name in this system: Oxygen; Traditional name: Air; Signs: Gemini, Libra and Aquarius.
Name in this system: Water; Traditional name: Water; Signs: Cancer, Scorpio and Pisces.
These are the names the system uses to describe behavioral tendencies and ways of expressing activity. To find your Sun sign and the other points of your chart, use your birth data and the corresponding chart. Comparing a couple requires knowing both charts.
In this reading, the Water signs (Cancer, Scorpio and Pisces) have an affinity with the Silicates signs (Taurus, Virgo and Capricorn). Both groups are described as more receptive or unhurried, so they may recognize a similar rhythm in the other person.
The Hydrogen signs (Aries, Leo and Sagittarius) and the Oxygen signs (Gemini, Libra and Aquarius) are also considered to have an affinity. Their nature is described as more expansive and geared toward action, whether physical or mental.
Similarity between groups is a first approximation. The other points of both charts, together with the experiences in inventory 1, complete the reading.
One person’s Sun sign and the other’s Ascendant
Another affinity I observe appears when one person’s Sun sign matches their partner’s Ascendant. For example, a person with the Sun in Cancer may become involved with someone whose Ascendant is Cancer; or a person with a Scorpio Ascendant may meet someone whose Sun sign is Scorpio.
The natal sign we mean here is the Sun sign. To identify the Ascendant you need the chart data, including the time of birth. Different Ascendants can occur over the course of a single day, so sharing a birth date is not enough to conclude that two people have the same one.
In this approach, the Ascendant describes another facet of the way we present ourselves, one related to personality traits and physical features. I have sometimes observed that this facet becomes more visible over the years, and that a person recognizes themselves in their Ascendant as much as, or more than, in their Sun sign.
Drawing on my experience of study and consultation, I also read it as a defense we build to face the world. That is why, when we meet someone whose Ascendant matches our Sun sign, we may feel we are facing a part of ourselves.
That part may awaken admiration or feel uncomfortable. In consultation, some people tell me that the sign of their Ascendant is precisely the one they find hardest to deal with. In my reading, that reaction invites them to explore what they recognize in themselves, or reject, when they meet others.
The relationship may feel like “can’t live with you, can’t live without you.” When they are together, both people feel drawn to each other and can talk as if time stood still. Yet while they are apart, they may not think much about each other. The interest comes back once they share the same space again.
If you don’t know your Ascendant or your partner’s, you can use the resources in the appendix to get the charts. Knowing it will let you follow the descriptions more clearly.
One person’s Sun sign and the other’s Descendant
When one person’s Sun sign matches the other’s Descendant, the latter may recognize in them traits of the partner they long for. The Descendant is linked to the 7th house, and among the matters it represents is the partner in marriage or commitment. That commitment can take whatever form both people agree on.
To tell the two positions apart, imagine that A has the Sun in the sign on B’s Descendant. In this interpretation, B may see A as an especially attractive figure to form a couple with.
That attraction need not be felt with the same intensity in both directions. To understand what A experiences, we also have to look at the contacts their own chart receives. One person’s expectations may differ from the other’s, even when they share a bond that one of them lives very intensely.
That is why we also need to look at A’s experience. An intense attraction on B’s side leaves open the question of what the other person feels.
Harmonious aspects between Venus and Venus
In this system, Venus is related to the way we express and receive affection. Its position in each sign describes different ways of approaching, showing tenderness and recognizing the other person’s expressions of it.
A harmonious aspect between the Venus of both charts is associated with affinity in that exchange and with what we usually call “chemistry.” We may feel that affection flows in a way we find pleasant or familiar.
For this comparison I use contacts by conjunction, sextile or trine: angles of 0°, 60° or 120°, respectively, with a maximum orb of 4° from the exact aspect. The orb is the margin allowed around that angle when considering the contact.
The expressions of Venus in the signs and its contacts have texts of their own. As you read them, notice how you give and receive affection, and how your partner experiences that exchange.
One person’s Sun and the other’s Moon in the same sign
Another form of attraction I consider is when the sign of one person’s Sun matches the sign of their partner’s Moon.
In the language of this system, the Sun is related to the way we mark out and defend our territory, while the Moon represents the imagination and the fantasies that run through our minds. The account draws on the image of yang and yin: the active principle, traditionally associated with the masculine, and the receptive one, associated with the feminine.
Here these names work as an analogy for complementary forces, without assigning anyone a fixed role according to their gender. From that perspective, sharing the sign of the Sun and of the Moon can feel like a meeting between two different expressions that recognize and attract each other. It is one of those affinities that bring a sense of magic to the relationship.
Recognizing an affinity without taking it for granted
Which shared moments make you feel that closeness? Do you know whether your partner experiences them the same way? Naming those moments helps you both recognize what you want to look after, and keeps you from assuming that the other enjoys exactly the same things.
The combinations of Sun signs have their own guide. You can read your couple’s combination with that question about the meeting in mind: what you enjoy, what you find hard and how each tendency shows up in the relationship you share.