Synastry – The Astrology of Relationships


Synastry reveals the cosmic connections between two birth charts, illuminating the unique dynamics of any relationship. Each planetary placement tells a story about love, communication, and emotional bonds. Explore the sections below to discover how your chart interacts with a partner’s—and what it means for your relationship. Get a free synastry chart below.

Free Synastry Chart

How to Read a Synastry Chart

Synastry charts compare two birth charts to reveal relationship dynamics—how your planets interact and what that means for love, marriage, communication, and long-term compatibility.

Key steps to reading a synastry chart:

  1. Overlay the Charts – Compare both birth charts to see how planets interact.
  2. Check Sun, Moon & Rising – These reveal core compatibility and emotional connection.
  3. Look at Key Aspects – Conjunctions, squares, and oppositions show attraction & challenges. Sextiles and trines are considered the softer aspects. Explore the Synastry Aspects That Define Your Relationship ->
  4. Analyze House Placements – Where do their planets fall in your chart? This shows how they impact different areas of your life. See What Your Houses Reveal About Your Love Life ->
  5. Interpret Outer Planets – Saturn, Uranus, Neptune, and Pluto can indicate karmic ties and long-term influence. Discover How Planets Shape Relationship Compatibility ->
  6. Want more information about how to read a synastry chart. Step-by-Step Guide to Reading Your Synastry Chart ->

Synastry FAQs

What is synastry in astrology?

Synastry is the study of how two birth charts interact, revealing the strengths, challenges, and dynamics of a relationship. It helps astrologers understand compatibility, emotional bonds, and long-term potential.

What does the word “synastry” mean?

The word synastry comes from Greek, meaning bringing together of stars. In astrology, it refers to comparing two natal charts to analyze relationship dynamics.

What are the “big three” in synastry?

The Big Three usually refer to the Sun, Moon, and Rising Sign in a birth chart. In synastry, they play a key role in compatibility—Sun shows core identity, Moon reflects emotions, and the Rising Sign influences attraction and first impressions.

What synastry aspects indicate true love?

Strong Venus, Moon, and Jupiter aspects—especially conjunctions and trines—often point to deep emotional connection and long-term harmony. However, even challenging aspects like Pluto or Saturn can indicate intense, transformative love.

How accurate is synastry in astrology?

Synastry can highlight relationship dynamics and patterns, but it’s not a guarantee of success or failure. Free will, life circumstances, and personal growth also play major roles in any relationship.

Does synastry predict relationship success?

Synastry reveals compatibility, attraction, and potential challenges, but a strong relationship requires mutual effort, communication, and emotional intelligence.

Which planet is most important in synastry?

Venus (love & attraction) and the Moon (emotional bonds) are key in romantic synastry, while Mars (passion & conflict) and Saturn (commitment & lessons) also play major roles.

What house is most important in synastry?

The 7th house (partnerships), 5th house (romance), and 8th house (intimacy & transformation) are particularly significant in love-based synastry.

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