Relationship astrology: synastry, overlays & composite charts

What is relationship astrology?

Relationship astrology is a broad label for astrological approaches to relationships. Synastry compares separate charts; a midpoint composite constructs a derived chart, while a Davison method derives a time and location before calculating a chart.

The subject can include partners, friends, family members and colleagues. John Green’s discussion with Chris Brennan describes a comparison grounded in each natal chart. Our library uses that starting point and makes the calculation rules visible before exploring symbolic questions.

Choose the question you want to answer

“What does this line between our planets mean?”

Open synastry aspects. Identify both placements, check their angle and read the orb allowance before considering a symbolic theme.

“Whose house is this planet in?”

Open house overlays. Name the receiving chart and its house method, then compare the reverse direction separately.

“Why does our relationship chart have a different Sun?”

Open composite charts. A derived midpoint is not either person’s natal position. The article also distinguishes the Davison method.

A bi-wheel is a display, not a verdict

A bi-wheel places two sets of chart positions on rings around one centre. It can help a reader keep the two datasets apart, but the chart labels and settings still matter. Software may also provide an inter-chart grid or an aspect list; Astro Gold’s manual documents these different views.

Before reading a line, identify which chart supplies each endpoint. Before reading a house, identify whose boundaries are shown. Changing which chart is drawn inside can change the house question without changing the angle between the same two planetary positions.

A reading order you can return to

1. State the purpose. Are you learning a technique, discussing a shared question or comparing two reports?
2. Check each record. Keep the birth data, time certainty and coordinate settings with the appropriate person.
3. Read each natal context. Avoid treating a cross-chart label as the whole account of either individual.
4. Choose one operation. Calculate a cross aspect, locate an overlay or inspect a composite construction. Record its rules.
5. Ask a concrete question. Let each person describe their own experience; retain differences and counterexamples.
6. Review the conclusion. Separate what was calculated from what was suggested and what the people actually reported.

Two charts mean two sets of uncertainties

A precise birth time for one person does not repair a missing time for the other. Which parts remain usable depends on the question: a receiving house boundary, a Moon longitude and a constructed composite angle have different input needs.

Keep unknowns visible rather than filling them with an unlabelled assumed time. The birth-time guide explains the general problem; the three entries here show where it enters a relationship comparison.

Keep the interpretation open to real answers

An original exercise: each person names one recurring situation they would like to handle more clearly—making plans, discussing expenses or finding time alone. Write down what usually happens before looking for an astrological theme. Then ask whether the symbolic vocabulary adds a useful question.

Keep a note of what does not fit. If the description suggests ease but the people describe a problem, their account remains the relevant evidence about the relationship. A chart cannot supply consent or establish another person’s private intentions.

These pages explain methods and invite reflection. They do not offer compatibility percentages, soulmate identification or a forecast of how long a relationship will last. Continue with the planet vocabulary, house reference and A–Z glossary as needed.