Synastry how-to
Synastry vs. Composite vs. Davison: What Each Chart Is For
These three relationship-astrology techniques are built differently and answer different questions. Use this decision framework to choose the chart before you start interpreting it.
01
The fastest distinction is how each chart is constructed
Synastry, midpoint composite, and Davison relationship charts are often grouped under “relationship astrology,” but they are not three versions of the same wheel. Synastry keeps two natal charts intact and compares them. A midpoint composite calculates a new set of planetary positions from the midpoints between matching natal placements. A Davison relationship chart is calculated for a midpoint in birth time and geographic space, producing a chart for an actual date and time rather than a set of direct planetary midpoints.
Because the construction changes, the subject of interpretation changes too. Choosing a method by habit can lead to asking one chart a question it is poorly designed to answer. Start with the question, then choose the technique.
02
Use synastry when the sentence contains “you” and “me”
Synastry is the clearest first choice for person-to-person interaction. It can show that one person’s Moon receives the other person’s Mercury, that one Venus contacts the other Mars, or that Saturn from one chart touches a personal planet in the other. Direction matters: A-to-B can feel different from B-to-A because the planets still belong to specific people.
This makes synastry useful for questions such as: Why do our conversations accelerate so quickly? Which person feels a particular Saturn pressure? Where does attraction arise? How do house overlays differ in each direction? If you need ownership, synastry preserves it.
03
Use a midpoint composite when the sentence contains “we”
A composite chart is a mathematical third chart made from midpoint positions. Astrologers use it to describe the pattern that appears when the relationship functions as a unit: its shared center, emotional climate, communication habits, values, pace, and recurring internal tensions. The composite Sun, Moon, Mercury, Venus, Mars, and their aspects become the primary language.
The trade-off is that ownership is blurred. A stressed composite Mercury can describe a communication pattern, but it cannot tell you which person is more likely to shut down or press harder. That is why composite usually works better after synastry, not instead of it.
04
Davison uses a midpoint in time and place rather than direct planet-to-planet midpoints
A Davison relationship chart is calculated from the midpoint of the two births in time and geographic space. Because the result corresponds to a real date and time, the planetary positions form an astronomically possible sky for that moment. This differs from a midpoint composite, where each planet is averaged separately and the resulting combination does not have to correspond to any single real sky.
Software can offer more than one geographic convention for Davison calculations, such as different ways of averaging locations or correcting the chart. If you use the method, note which convention the calculator actually applies. “Davison” is a technique family, not a reason to hide the calculation settings. Velvet Zodiac’s current standalone Davison tool names the uncorrected variant explicitly: it uses the midpoint UTC instant and arithmetic mean latitude/longitude, flags method-sensitive edge cases, scans declared approximate-time windows, and withholds the layer when a clock time is completely unknown.
05
A “real sky” does not automatically make Davison more true
It is tempting to rank techniques and say Davison is more real because it corresponds to a date and time, while composite is more abstract. That describes their construction, not their proven accuracy. Astrologers disagree about which relationship chart they prefer and how much weight to give each one. There is no need to turn a method difference into a hierarchy of truth.
A more disciplined approach is to use the technique consistently enough to learn what kinds of questions it helps you answer. If you switch methods every time one chart gives a more appealing result, you are selecting for the interpretation you want rather than testing a coherent practice.
06
Choose by question, not by which wheel looks nicer
If your question is “Why does my Moon react so strongly to your Mars?” choose synastry. If it is “What communication system do we seem to create together?” choose composite. If you intentionally practice Davison and want to examine the relationship through a chart anchored to a midpoint date and location, choose Davison. For a first relationship reading, synastry plus composite is usually enough to keep the method understandable.
You do not gain depth by opening every chart type at once. More charts can simply create more opportunities to cherry-pick a dramatic placement.
07
The methods can echo each other without becoming independent proof
Suppose synastry emphasizes Mercury and the composite also has a strongly aspected Mercury. Communication is a reasonable theme to investigate. If a Davison chart also emphasizes Mercury, an astrologer who uses Davison may find the repetition noteworthy. But all three methods ultimately depend on the same two birth datasets, so repetition should not be presented as independent scientific confirmation.
Use echoes to ask a more exact question: Is the person-to-person pattern verbal speed, emotional misunderstanding, intellectual excitement, planning, or conflict? Does the shared relationship system amplify or regulate that pattern? Specificity is more useful than counting how many charts mention Mercury.
08
Birth-time quality affects the three techniques differently
Synastry aspects between slower planets can remain usable with an uncertain birth time, while Ascendant contacts and houses can become unreliable quickly. Composite angles and houses also depend on the input times. Davison calculations are explicitly built from birth time and location, so input uncertainty must change the output confidence. Velvet Zodiac scans declared approximate-time windows and labels what survives; a completely unknown clock time withholds the Davison layer rather than manufacturing an event-like chart.
When time quality is weak, narrow the technique rather than pretending nothing changed. Use stable planetary contacts, label time-sensitive observations, and avoid exact house or angle claims that the data cannot support.
09
A three-step decision tree keeps the reading clean
Step one: identify the noun in the question. Is it Person A, Person B, or the relationship as a unit? Step two: choose the least complicated technique that can answer that question. Step three: write one or two observable expectations before opening another chart. This keeps interpretation from drifting every time a new symbol appears.
For most readers, the practical sequence is natal context → synastry → composite. Add Davison only when you understand why you want that method and what calculation convention you are using. A smaller number of well-read charts is usually more informative than a stack of wheels interpreted without hierarchy.
10
None of the three charts can make the relationship decision for you
Synastry can symbolize interaction, composite can symbolize shared pattern, and Davison can provide another relationship-chart framework. None can measure consent, guarantee longevity, prove compatibility of life goals, diagnose abuse, or decide whether two people should commit or separate. Those questions depend on direct evidence and personal choice.
Use the charts to improve the questions you ask about a relationship, not to outsource the answers. The best technique is the one whose construction matches your question and whose interpretation stays accountable to what the people involved actually experience.
Common questions
Synastry vs. Composite vs. Davison: What Each Chart Is For FAQ
What is the main difference between synastry and a composite chart?
Synastry compares two separate natal charts and preserves direction between the people. Composite merges matching placements into midpoint positions and is read as a shared relationship pattern.
How is a Davison chart different from a midpoint composite?
Davison is calculated from a midpoint in birth time and geographic space, producing a chart for an actual date and time. A composite averages matching planetary positions directly.
Do I need synastry, composite, and Davison for every relationship reading?
No. Start with natal context and synastry, add composite when you want the shared relationship pattern, and use Davison only if that technique fits your practice and question.
Velvet Zodiac takeaway