Real synastry · a score you can see the maths of

Two skies,
read as one.

Astra takes both your birth charts, computes the real aspects between them, and reads how the two of you meet — with a compatibility score whose weights are printed right on the page. Any pairing: partners, friends, family, colleagues.

Read our compatibility ✦ The score, free.
Real ephemeris, both charts Every inter-aspect, computed A score with published weights For reflection & entertainment
Why read two charts

Not a quiz. A conversation between two skies.

Synastry is the old art of laying one chart over another and reading where they meet. Astra does it from the real sky — and, unlike a black-box “you're 92% compatible”, shows you exactly how the number is built.

See the pull

Where your planets touch theirs — the trines that flow, the squares that spark, the Sun-and-Moon contacts at the heart of it.

Read the weather

Where the two of you move in step, and where you'll each have to translate. Growth edges, not red flags.

Trust the number

A transparent score from three published components with weights you can see — no hidden magic, same inputs, same result.

Free · under a minute

Read your compatibility.

Two sets of birth details in, your score and both big-threes out. Computed privately in your browser — nothing shared, nothing stored on a server.

Two birth charts

A The first person

B The second person

Both charts computed live in your browser — nothing stored on a server

Your compatibility

Here's how you meet.

The full reading

Unlock your full compatibility reading.

$8.99one-time

The score is only the door. Inside: the whole synastry read in warm, plain language — every strong contact between your charts, what flows and what stretches, and an “Ask Astra about us”.

  • The full written relationship reading (both charts)
  • Every strong inter-aspect, named and explained
  • The score breakdown, every weight shown
  • Both big-three decks, side by side
  • “Ask Astra about us” — grounded in both charts
  • Printable / save-as-PDF, yours to keep

Instant, in your browser. A reflective, for-entertainment reading of two charts — inclusive of any bond, and never advice about whether to stay or go.

The difference

A “love calculator”, or your two charts?

A sun-sign match app
  • Knows two things: two Sun signs
  • A number with no maths behind it
  • Assumes romance, assumes a verdict
  • “You're 92% compatible” — because it says so
Your Astra synastry
  • All ten planets in each chart, and the aspects between them
  • A score from three components — with the weights printed
  • Inclusive of any bond; never a stay-or-leave verdict
  • Real ephemeris positions, read in plain language
The full reading

Both decks, every contact, one reading.

Your two big-threes dealt side by side, the strongest aspects between your charts, and a warm synthesis of how the two skies meet.

See it first

A contact, and how it reads.

A · ☽ Moon
Cancer
B · ♀ Venus
Taurus
Sample — a Moon–Venus trine

A's Moon trines B's Venus. One of you feels the room; the other loves through comfort and care — and here those instincts run downhill toward each other. Ease tends to arrive early between you, the kind that feels like being understood without explaining…

The full reading gives a passage like this for every strong contact between your charts — the flowing ones and the stretching ones alike.

Questions

Before you read.

Does this only work for couples?
No — synastry reads any two charts. Tell Astra whether it's partners, friends, family or colleagues and the reading speaks that language. It describes how two people meet, not who should be dating whom.
How is the score calculated?
From three published components: Element Harmony (how the two Suns' and Moons' elements relate), Aspect Quality (the tenor of the whole grid of aspects between the charts), and Luminary Connection (the Sun-and-Moon contacts between you). They're blended 30% / 40% / 30% into one figure, capped at 96 — no perfect scores. Every weight and table is shown on your reading. Same inputs, same score, always.
Do we both need exact birth times?
Not to start. Every planet's sign and the aspects between your charts come from the birth dates and places alone. Birth time sharpens the Moon and unlocks each Rising and the houses — add it where you know it, or tick “Unknown” and Astra reads honestly without it.
Will it tell us whether to stay together?
No — and by design it won't. Astra doesn't give stay-or-leave advice, predict a relationship's future, or hand down a verdict. It's a reflective, for-entertainment mirror on two skies meeting: where you flow, where you stretch, and what each of you might understand about yourselves.
How is our data handled?
Both charts are computed on your device — your birth details aren't sent to a server to be drawn, and they're never sold. Your email is used to send your reading and, if you choose, occasional related notes.
Your full compatibility reading is ready — $8.99