Synastry aspects
The synastry aspect dictionary
Forty contacts between two birth charts, from the Venus-Mars spark to the quiet Sun-Moon kind of home. What each one feels like, how often it really happens, and whether the two of you have it.
Photo: nanessa reyes / Burst
At a glance
A synastry aspect is an angle between a planet in your chart and a planet in theirs. In 599,995 random pairs we tested, Venus conjunct Mars turned up in 6.5% (either direction) and Sun conjunct Moon in 8.7%.
- Most common here
- Uranus square Mars12.9% of pairs
- Rarest here
- Venus opposite Venus3.2% of pairs
- Double whammy
- 4%chance the reverse also happens, once one way is in
- Tight (under 1°)
- 19%of hits, on average
- Out of sign
- 10%of hits cross a sign line
Check the two of youTwo birth dates. Every contact here, both directions.
Start here
What a synastry aspect actually is
Try this today
- Start with the lights and the love planets: Sun, Moon, Venus, Mars. They are the contacts you notice first.
- Then the angles (the Ascendant), which need an exact birth time.
- Only then the slow planets and points, which many people born near you share.
You lay one birth chart over another and measure the angles between them. If your Venus is at 12° Leo and their Mars is at 14° Leo, the two points are 2° apart: that is Venus conjunct Mars, within orb. That is all a synastry aspect is.
The five classic angles are the conjunction (0°), sextile (60°), square (90°), trine (120°) and opposition (180°). Conjunctions blend two planets. Trines and sextiles let them cooperate. Squares and oppositions make them rub, which is less doom than it sounds: friction is how two people learn each other.
Every aspect has a direction. Your Venus to their Mars is not the same contact as their Venus to your Mars, and each person tends to feel it from their own side. Every page in this dictionary covers both sides.
How close counts
Orbs: the one rule that changes every answer
Try this today
- Run the checker below and look at the degrees, not just yes or no.
- Anything under 2° deserves a full read. Anything at the edge of the orb is a whisper.
An aspect is rarely exact. The orb is how far from exact you still count it. Astrologers disagree on orbs, which is why two sites can give the same couple different answers.
Ours is stated on every page: conjunction, opposition, square, trine 6 deg; sextile 4 deg; +2 deg with the Sun or Moon; 3 deg with a lunar node or Lilith. The Sun and Moon get more room because they are the most personal points; Lilith and the nodes get less because they are calculated points that would otherwise turn up for almost everyone.
Inside the orb, closer is louder. Across this dictionary, about 19% of the pairs that have a contact have it inside 1°. Those are the ones people describe without being asked.
Double whammy
When it runs both ways
A double whammy is when an aspect happens in both directions: your Venus on their Mars and their Venus on your Mars. Astrologers give it extra weight because each person lives both sides of the story.
It is rarer than single contacts, because two separate alignments have to happen at once. Our sample shows how rare: Venus conjunct Mars turns up one way in 3.3% of pairs, but both ways in only 0.14%, about 1 in 735.
There is a twist. Once one direction is in orb, the reverse happens much more often than chance, about 4% of the time across this dictionary. Two people born at similar times of year share a lot of sky.
Same-planet contacts like Moon square Moon are automatically mutual, so they never get a double whammy flag.
Rarity
How often these contacts really happen
We did the counting so you do not have to guess. We drew 120,000 random births between 1950 and 2010, paired them 599,995 times, and tested every aspect in this dictionary.
The most common contact here is Uranus square Mars, in 12.9% of pairs either way. Squares turn up roughly twice as often as conjunctions because there are two ways to make one, which is why Moon square Moon is so common (8.8%).
The rarest is Venus opposite Venus at 3.2%: node and Lilith contacts use a tight orb, and the Ascendant needs both birth times to line up. North Node conjunct Ascendant sits at 3.2%, which is why it feels so striking when you find it.
Slow planets have a catch: everyone born within a year or two of each other shares roughly the same Saturn, Uranus, Neptune and Pluto. For those, the age gap between you decides more than anything else. Each page shows its own age-gap table.
Check your pair
Which of these contacts do you two have?
Enter both birth dates. The checker computes both charts in your browser and tests all 40 contacts, both directions, with the orbs above. Double whammies are flagged. Add birth times for the Ascendant and an exact Moon. Nothing is stored.
Enter two birth dates to see your contacts. A time is only needed for the Ascendant, and makes the Moon exact.
More to read
Shorter reads. Each opens in place.
The dictionary
All 40 contacts
Love planets and lights: Venus conjunct Mars · Sun conjunct Moon · Moon square Moon · Moon conjunct Venus · Venus opposite Mars · Venus opposite Venus · Mars square Venus · Sun opposite Moon · Mercury conjunct Venus
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The Ascendant (needs birth times): Moon conjunct Ascendant · Venus conjunct Ascendant · Mars conjunct Ascendant · Sun conjunct Ascendant · Saturn conjunct Ascendant · Jupiter conjunct Ascendant · Sun opposite Ascendant · Pluto conjunct Ascendant
Slow planets: Saturn conjunct Moon · Pluto square Venus · Pluto conjunct Venus · Uranus square Mars · Uranus conjunct Sun · Pluto square Mars · Jupiter conjunct Moon · Saturn conjunct Sun · Saturn opposite Venus · Pluto opposite Venus · Neptune conjunct Moon · Neptune conjunct Venus · Pluto conjunct Moon
Lilith and the lunar nodes: Lilith conjunct Venus · North Node conjunct Ascendant · South Node conjunct Venus · Venus conjunct North Node · North Node conjunct Sun · Lilith square Venus · Lilith conjunct Moon · South Node conjunct Moon · Lilith conjunct Mars · North Node conjunct Moon
Method
How we chose these forty
On 2026-10-18 we ran Google's public autocomplete for prefixes like "venus conjunct" and "synastry moon", scored 830 point-aspect-point combinations by how often and how high they appeared, then kept the forty with the most demand among points we can compute reliably (Vertex, Juno and Chiron are left out for now).
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Positions come from NASA JPL's DE442 ephemeris; the mean node and Black Moon Lilith use Meeus's mean lunar elements. We spot-checked them against the Swiss Ephemeris to within a few hundredths of a degree.
How common each contact is
From 599,995 random pairs of births, 1950 to 2010. "One way" is person 1's first point to person 2's second point. "Either" counts both directions. "Both" is the double whammy.
| Aspect | Orb | One way | Either way | Both ways |
|---|---|---|---|---|
| Uranus square Mars | 6° | 6.69% | 12.94% | 0.44% |
| Mars square Venus | 6° | 6.69% | 12.91% | 0.46% |
| Pluto square Mars | 6° | 6.61% | 12.83% | 0.44% |
| Pluto square Venus | 6° | 6.57% | 12.65% | 0.43% |
| Moon square Moon | 8° | 8.85% | 8.85% | always mutual |
| Sun opposite Moon | 8° | 4.49% | 8.75% | 0.21% |
| Neptune conjunct Moon | 8° | 4.48% | 8.73% | 0.19% |
| Sun opposite Ascendant | 8° | 4.46% | 8.72% | 0.20% |
| Jupiter conjunct Moon | 8° | 4.46% | 8.72% | 0.20% |
| Moon conjunct Ascendant | 8° | 4.42% | 8.71% | 0.19% |
| Sun conjunct Ascendant | 8° | 4.46% | 8.70% | 0.20% |
| Moon conjunct Venus | 8° | 4.44% | 8.69% | 0.19% |
| Saturn conjunct Sun | 8° | 4.44% | 8.69% | 0.21% |
| Pluto conjunct Moon | 8° | 4.43% | 8.69% | 0.22% |
| Uranus conjunct Sun | 8° | 4.42% | 8.68% | 0.20% |
| Sun conjunct Moon | 8° | 4.43% | 8.67% | 0.19% |
| Saturn conjunct Moon | 8° | 4.45% | 8.66% | 0.21% |
| Pluto conjunct Ascendant | 6° | 3.98% | 7.75% | 0.16% |
| Mars conjunct Ascendant | 6° | 3.46% | 6.77% | 0.12% |
| Pluto conjunct Venus | 6° | 3.41% | 6.71% | 0.12% |
| Saturn conjunct Ascendant | 6° | 3.33% | 6.62% | 0.11% |
| Neptune conjunct Venus | 6° | 3.34% | 6.59% | 0.11% |
| Venus conjunct Ascendant | 6° | 3.35% | 6.55% | 0.11% |
| Pluto opposite Venus | 6° | 3.36% | 6.55% | 0.10% |
| Venus opposite Mars | 6° | 3.35% | 6.54% | 0.14% |
| Lilith square Venus | 3° | 3.33% | 6.54% | 0.11% |
| Venus conjunct Mars | 6° | 3.34% | 6.52% | 0.14% |
| Saturn opposite Venus | 6° | 3.29% | 6.50% | 0.11% |
| Jupiter conjunct Ascendant | 6° | 3.29% | 6.46% | 0.11% |
| Mercury conjunct Venus | 6° | 3.33% | 6.32% | 0.29% |
| Venus conjunct North Node | 3° | 1.67% | 3.33% | 0.03% |
| Lilith conjunct Moon | 3° | 1.68% | 3.32% | 0.03% |
| North Node conjunct Moon | 3° | 1.70% | 3.32% | 0.03% |
| North Node conjunct Sun | 3° | 1.67% | 3.31% | 0.03% |
| Lilith conjunct Venus | 3° | 1.69% | 3.30% | 0.03% |
| Lilith conjunct Mars | 3° | 1.66% | 3.30% | 0.03% |
| South Node conjunct Venus | 3° | 1.66% | 3.26% | 0.03% |
| South Node conjunct Moon | 3° | 1.64% | 3.26% | 0.03% |
| North Node conjunct Ascendant | 3° | 1.64% | 3.24% | 0.03% |
| Venus opposite Venus | 6° | 3.23% | 3.23% | always mutual |
All times are UTC. In the Americas the local date can be a day earlier; in Asia and Australia a day later.
Quick answers
What are the most important synastry aspects?
Most astrologers start with contacts between the Sun, Moon, Venus, Mars and the Ascendant: Sun conjunct Moon for belonging, Venus conjunct Mars for attraction, Moon conjunct Venus for tenderness, and the Ascendant contacts for first impressions. Saturn contacts are read for staying power.
What is a double whammy in synastry?
It is when an aspect happens in both directions, for example your Venus on their Mars and their Venus on your Mars. In our sample Venus conjunct Mars was mutual in only 0.14% of pairs.
What orb should I use for synastry aspects?
There is no single rule. We use conjunction, opposition, square, trine 6 deg; sextile 4 deg; +2 deg with the Sun or Moon; 3 deg with a lunar node or Lilith. Tighter is always stronger.
Do synastry aspects work without a birth time?
Mostly. Planets from the Sun to Pluto barely move in a day, so dates are enough. The Moon can be off by up to about 7 degrees without a time, and the Ascendant needs an exact time.
Are squares and oppositions bad in synastry?
No. They describe friction and difference, which can be hard work but is also how couples grow. Many long relationships are full of them. Look at how two people handle them, not just whether they exist.
Is synastry the same as compatibility by Sun sign?
No. Sun sign compatibility compares two signs. Synastry compares whole charts, degree by degree, so two people of 'incompatible' signs can still share strong, easy contacts.
Who feels a synastry aspect more?
Each person feels it from their own side. The person whose faster, more personal point is involved (often the Moon or Venus) usually reports it more strongly, but both notice.
