Synastry: Relationship Astrology
How Two Charts Interact
Learn how to use synastry — the comparison of two birth charts — to understand relationship dynamics, compatibility, and growth areas between partners.
What Is Synastry?
Synastry is the art of comparing two birth charts to understand the dynamics between two people. By overlaying one chart on another, we can see how the planets in Person A's chart interact with the planets in Person B's chart. These inter-chart aspects reveal areas of attraction, compatibility, tension, and growth.
Key Synastry Aspects to Look For
- Sun-Moon connections — The most important for long-term compatibility. Sun conjunct Moon or Moon trine Sun creates natural understanding.
- Venus-Mars aspects — Physical attraction and romantic chemistry. Conjunctions and trines indicate strong magnetism.
- Moon-Moon aspects — Emotional compatibility. How well you understand each other's needs.
- Ascendant connections — Physical attraction and first impression compatibility.
- Saturn aspects — Commitment, longevity, but also potential restriction. Saturn-Venus can be binding.
- Outer planet contacts — Deep, transformative connections (Pluto), spiritual bonds (Neptune), or electric attraction (Uranus).
House Overlays
Where someone's planets fall in your houses shows which areas of your life they activate. If their Sun falls in your 7th house, they naturally fill a partnership role. If their Mars falls in your 10th house, they motivate your career ambitions.
Using Synastry in Zodisphere
- Open the Synastry Panel from the analysis toolbar
- Enter birth data for both people
- View all inter-chart aspects with orbs and strength indicators
- The panel highlights the most significant connections
- Check the Composite Chart Panel for the relationship's own "birth chart"
Frequently Asked Questions
Can synastry predict if a relationship will work?
Synastry shows the dynamics and potential of a relationship, not its guaranteed outcome. Two people with "perfect" synastry might not work due to individual readiness, while challenging synastry can produce deep, transformative bonds. Astrology informs; it doesn't determine.
What's the difference between synastry and composite charts?
Synastry overlays two separate charts to see how they interact. A composite chart creates a single new chart (by finding the midpoints between each pair of planets) representing the relationship itself as an entity.
Which aspects are most important in synastry?
Sun-Moon aspects are most important for long-term compatibility. Venus-Mars for attraction. Moon-Moon for emotional understanding. Saturn aspects for commitment and longevity.