What is synastry in astrology, and how is it used to compare two natal charts?

August 22, 2024

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What is synastry in astrology, and how is it used to compare two natal charts?

Synastry is a branch of astrology focused on the comparison and interaction of two individuals’ natal charts to evaluate their potential compatibility and relationship dynamics. The term “synastry” comes from the Greek word “syn,” meaning together, and “astron,” meaning star. It involves analyzing the positions of the planets in each person’s chart and how these positions relate to each other. This analysis can offer deep insights into the strengths, challenges, and overall energy of a relationship.

Key Components of Synastry

  1. Natal Charts: The foundation of synastry is the natal chart, which is a map of the sky at the exact time and place of a person’s birth. It includes the positions of the Sun, Moon, planets, and other celestial points like the Ascendant and Midheaven. Each chart is unique and reflects the personality, strengths, weaknesses, desires, and life path of the individual.
  2. Aspects Between Planets: In synastry, the aspects (or angles) between the planets in one person’s chart and the planets in the other person’s chart are crucial. These aspects reveal how the energies of the two people interact.
    • Conjunction (0°): When two planets are close together in the charts, their energies merge. This can create a strong bond, but whether it’s positive or negative depends on the planets involved.
    • Sextile (60°) and Trine (120°): These are harmonious aspects, indicating ease, compatibility, and mutual support in the relationship.
    • Square (90°) and Opposition (180°): These aspects are challenging, often indicating tension or areas where the individuals may need to work through conflicts.
  3. House Overlays: The houses in a natal chart represent different areas of life, such as relationships, career, home, and personal growth. In synastry, one person’s planets falling into specific houses in the other person’s chart can highlight which areas of life are most affected by their relationship. For example:
    • Planets in the 7th House: The house of partnerships suggests a strong focus on romantic relationships, marriage, or long-term commitments.
    • Planets in the 5th House: The house of creativity, romance, and children might indicate a fun, playful, or romantic connection.
    • Planets in the 8th House: The house of intimacy, transformation, and shared resources suggests deep, intense connections, often related to shared experiences or emotional bonds.
  4. Personal Planets: The Sun, Moon, Mercury, Venus, and Mars are the personal planets that most strongly influence an individual’s personality and daily experiences. In synastry, the interactions between these planets are critical in understanding the core dynamics of a relationship:
    • Sun Connections: How the core identities of the individuals interact. Positive aspects indicate mutual respect and shared goals, while challenging aspects may suggest ego clashes.
    • Moon Connections: Emotional compatibility and how the individuals nurture each other. Harmonious aspects suggest emotional understanding, while challenging aspects might indicate mismatched emotional needs.
    • Mercury Connections: Communication style and intellectual rapport. Positive aspects suggest easy communication, while challenging aspects might lead to misunderstandings.
    • Venus Connections: Love, affection, and attraction. Positive Venus aspects often indicate a strong romantic bond, while challenging aspects may show differences in values or romantic expectations.
    • Mars Connections: Physical attraction, drive, and conflict resolution. Positive aspects suggest strong sexual chemistry and mutual drive, while challenging aspects might indicate power struggles or conflicts.
  5. Outer Planets and Generational Influences: The outer planets (Jupiter, Saturn, Uranus, Neptune, and Pluto) move slowly and thus influence broader, generational traits. In synastry, these planets can indicate how the relationship is influenced by larger social, cultural, or generational factors, and how the couple might grow or be challenged over time.
    • Jupiter: Brings expansion, optimism, and shared growth. Positive Jupiter aspects suggest a relationship that encourages mutual growth and generosity.
    • Saturn: Represents discipline, structure, and long-term commitment. While positive aspects can bring stability, challenging Saturn aspects might indicate restrictions or heavy responsibilities within the relationship.
    • Uranus: Symbolizes change, innovation, and unpredictability. Strong Uranus aspects can make a relationship exciting but also unstable.
    • Neptune: Relates to dreams, illusions, and spirituality. Positive aspects may create a deep spiritual connection, but challenging aspects can lead to confusion or unrealistic expectations.
    • Pluto: Involves power, transformation, and intensity. Pluto aspects in synastry can indicate a transformative relationship, but also one with power struggles or deep emotional bonds.
  6. Composite Chart: While synastry examines the interaction between two charts, a composite chart combines them into a single chart that represents the relationship itself. This chart is calculated by finding the midpoints between the two individuals’ planets and angles. The composite chart is used to understand the overall purpose, dynamics, and direction of the relationship as a whole.

How Synastry is Used

  1. Relationship Compatibility: Synastry can provide insights into the overall compatibility between two people. By analyzing the aspects between their charts, astrologers can assess whether the relationship is likely to be harmonious, challenging, or a mix of both.
  2. Understanding Strengths and Challenges: Synastry helps couples understand the strengths they bring to the relationship, as well as potential challenges they may face. For instance, if one person’s Mars squares the other’s Venus, there might be issues around balancing desire and affection. Awareness of these dynamics can help couples navigate them more effectively.
  3. Timing and Development: By examining transits and progressions in synastry, astrologers can identify key periods when a relationship might go through significant changes, such as periods of growth, challenges, or deepening commitment. This can be especially useful in understanding why a relationship might feel different at different times and in planning for the future.
  4. Personal Growth Within Relationships: Synastry can also help individuals understand how their relationships contribute to their personal growth. Certain aspects might push them to develop new skills, confront fears, or learn important life lessons.
  5. Relationship Advice: Armed with insights from synastry, astrologers can offer advice on how to improve a relationship. This might include communication tips, ways to support each other’s emotional needs, or strategies for overcoming challenges.

Limitations of Synastry

While synastry can provide valuable insights, it’s important to approach it with a balanced perspective:

  • Not Deterministic: Astrology suggests potential tendencies and dynamics but doesn’t dictate the fate of a relationship. Free will and conscious effort play significant roles in the success of any partnership.
  • Complexity of Human Relationships: Relationships are influenced by many factors beyond astrological compatibility, such as upbringing, culture, personal values, and life experiences.
  • Need for Context: A single aspect or planetary placement should not be interpreted in isolation. The entire chart and the broader context of the relationship must be considered.

In conclusion, synastry is a powerful tool for understanding the intricate dynamics of romantic relationships, offering insights into compatibility, challenges, and potential for growth. By comparing two natal charts, it can reveal how individuals might interact, support each other, and navigate their shared journey. However, it should be used as a guide rather than a definitive answer to the complexities of human relationships.


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