What is Synastry
Synastry is a method of comparing two natal charts to analyze relationships between people. The word comes from the Greek “syn” (together) and “astron” (star) — literally “stars together.” This is the most precise astrological tool for understanding the dynamics of relationships.
Unlike popular “zodiac sign compatibility” tables, synastry analyzes the interaction of all planets, houses, and aspects in the charts of both partners. Two Aries individuals may be completely different as a couple — everything depends on the full picture.
How Synastry Works
The astrologer overlays the planets of one partner onto the natal chart of the other. For example, if one person’s Venus falls in the 7th house (the house of partnership) of the other, this is a strong sign of romantic attraction. If one person’s Saturn is conjunct the other’s Sun, there may be a sense of restriction or, conversely, stabilization.
Key Aspects in Synastry
Aspects are the angular distances between planets in two charts. The most important ones are:
- Conjunction (0°) — the strongest connection. Energies merge. A conjunction of the Sun and Moon is a classic example of an “ideal couple.”
- Trine (120°) — natural harmony and ease of communication. Partners intuitively understand each other.
- Sextile (60°) — opportunities for growth through the relationship. Effort is required, but the result is worth it.
- Square (90°) — friction and challenges. This does not mean incompatibility — it is a growth zone that keeps the relationship alive.
- Opposition (180°) — attraction of opposites. It can be both a magnetic pull and a source of conflict.
5 Most Important Synastry Factors
1. Sun — Moon Contacts
Harmonious aspects between one person’s Sun and the other’s Moon are the gold standard of compatibility. The Sun provides warmth and confidence, while the Moon offers emotional response and care. When these luminaries are in harmony, partners feel deep mutual support.
2. Venus — Mars Connections
This is the “chemistry” of the relationship. Venus governs how we love, and Mars governs how we desire. Aspects between them create physical attraction and romantic tension.
3. Moon — Moon Harmony
The Moons of the partners reveal emotional compatibility in daily life. If your Moons are in harmonious signs, you feel comfortable living together, and your emotional rhythms align.
4. Mercury — Mercury
How do you communicate? Do you understand each other? Harmony between Mercuries is the key to being able to negotiate even in difficult situations.
5. Saturn in Synastry
Saturn determines longevity. Harmonious aspects bring stability and commitment. Tense aspects can create a sense of control or coldness. However, without Saturn, relationships often remain superficial.
What Synastry Can Show
- Where you naturally harmonize and where conflicts arise
- Why you are drawn to this person (and why this pull may not always be “positive”)
- Which areas of shared life will be easiest and most challenging
- How to communicate more effectively with your partner
- The potential of the relationship for long-term partnership
Synastry vs. Composite Chart
Synastry shows how each partner influences the other. A composite chart is a chart of the relationship itself as a separate entity. Astrologers often use both methods together for a complete picture.
Common Synastry Myths
“No harmonious aspects = doomed relationship”
Not true. Tense aspects create dynamics and passion. Couples with mostly harmonious aspects may find each other boring.
“We are incompatible by sign”
The Sun sign is only one factor out of dozens. A full synastry can reveal deep compatibility even in “classically incompatible” pairs.
“Synastry predicts divorce”
No. Synastry shows potential and challenges. Relationships are built by people, not planets. Knowing the weak spots helps work on them consciously.
How to Order a Synastry Analysis
For synastry, you need the exact birth data of both partners: date, time, and place. Try our free synastry calculator for a basic analysis or order a professional relationship analysis from an experienced astrologer for a deeper understanding of your partnership.
