Guides · Synastry
Synastry aspects to avoid: the hard contacts and what they ask of you
The synastry aspects astrologers flag most often are hard contacts (squares, oppositions and some conjunctions) from Saturn, Pluto, Neptune or Uranus to a partner's Sun, Moon, Venus or Mars, and tight Mars squares to the other person's Mars or Venus. These describe friction: coldness, control, confusion or instability. None of them alone means a relationship will fail, and most long-lasting couples have several.
So "avoid" is really "know about". A hard contact tells you where the two of you will have to work. What matters is how tight it is, how many there are, whether easy contacts balance them, and what both of you do about it. Below: the hard aspects in one table, with orbs and what each tends to bring; the ones astrologers worry about most; the house overlays people fear; when a hard aspect is better than none; a checklist for your two charts; and when the problem isn't astrology at all. To follow along, get your free chart and your partner's.
Is there a synastry aspect that means "don't date"?
No. Astrologers disagree about which contacts are hardest, and none of them has a single aspect that always ends a relationship. Every chart pair has hard aspects: with ten planets each, there are a hundred planet-to-planet pairs between two charts, and some will fall in squares and oppositions by chance.
Two other points before the list. First, hard aspects bring energy as well as strain; many astrologers say a couple with only trines can drift because nothing pushes them to grow. Second, research hasn't shown that synastry predicts who stays together. A large test of astrology published in Nature in 1985 found astrologers couldn't match charts to personality profiles better than chance. Read what follows as a way to talk about patterns, not as a verdict.
The hard synastry aspects, ranked
Orbs are how far from exact an aspect is. These are common ranges; inside about 3° a contact is strong, and past the upper number most astrologers ignore it.
| Contact (one person's planet to the other's) | Aspects to note | Orb | What it tends to bring | What it asks of you |
|---|---|---|---|---|
| Saturn – Moon | conjunction, square, opposition | up to 6° | The Moon person feels judged, cold or held back; the Saturn person feels burdened by the other's moods. | Warmth said out loud; criticism softened. |
| Saturn – Venus | conjunction, square, opposition | up to 6° | Affection feels rationed; loyalty without fun. | Planned pleasure and praise. |
| Saturn – Sun | square, opposition | up to 6° | The Sun person feels controlled or doubted. | Room to lead; less correction. |
| Pluto – Venus / Moon | conjunction, square, opposition | up to 5° | Obsession, jealousy, power struggles; very strong pull. | Honesty about control; trust over checking up. |
| Mars – Mars / Mars – Sun | square, opposition | up to 6° | Competition, short tempers, fights over who leads. | Ground rules for arguing; shared goals. |
| Mars – Saturn | conjunction, square, opposition | up to 6° | One pushes, the other blocks; frustration, sexual tension that stalls. | Patience; agreeing on pace. |
| Neptune – Venus / Moon / Sun | conjunction, square, opposition | up to 5° | Idealising, then disappointment; vagueness, lies of omission. | Plain talk about facts and money. |
| Uranus – Venus / Moon | conjunction, square, opposition | up to 5° | Excitement, then distance; on-off patterns. | Space built into the relationship. |
| Mercury – Mercury | square, opposition | up to 5° | Talking past each other; small arguments that grow. | Slower conversations; writing things down. |
| Moon – Moon | square | up to 6° | Different emotional needs and rhythms. | Asking, not assuming. |
| Saturn – Nodes | conjunction, opposition | up to 3° | Some astrologers read it as heavy, karmic duty; others as commitment. | Checking it isn't only duty. |
Contacts that touch the Sun, Moon, Venus, Mars or the Ascendant are felt most. Contacts between slow planets (Saturn to Saturn, Pluto to Neptune) are often generational: everyone born within a few years of you shares them.
Saturn contacts: the ones astrologers mention first
Saturn is the planet of limits, duty and time. Between two people it is the classic "glue" aspect: many long marriages have Saturn touching a personal planet. It is also the aspect most often called the hardest, because the same contact that brings loyalty brings criticism.
- Saturn on the Moon: most often named as the hardest. The Moon person can feel they're never quite allowed to feel; the Saturn person can feel they're always looking after someone. Couples who do well with it name the pattern and build warmth on purpose.
- Saturn on Venus: love that is serious from the start. Good for commitment, hard for romance. Watch for one person withholding affection as control.
- Saturn on the Sun or Mars: one person feels held back. Works better when the Saturn person acts as support, not supervisor.
Saturn's easy contacts (trines, sextiles) are among the aspects astrologers like most for staying power. See synastry aspects for marriage for that side.
Pluto contacts: intensity and control
Pluto between two charts brings depth and a sense that the relationship changes you. The hard forms bring jealousy, possessiveness and arguments about power. Pluto to Venus or the Moon is the contact most linked to "I couldn't stay away even though it hurt". It is also on most lists of attraction aspects, which is why it's confusing: the pull is real, and so is the strain. More on the pull in synastry aspects that indicate attraction.
Neptune contacts: love that blurs
Neptune dissolves edges. Touching the Sun, Moon or Venus it can bring tenderness and a spiritual feeling, or a fog where you see who you hoped for, not who's there. The hard forms are linked to disappointment, avoidance, money confusion and small lies. The fix astrologers give is unromantic: talk plainly, check facts, keep money clear.
Uranus contacts: excitement and distance
Uranus on Venus or the Moon is instant chemistry and an unsettled feeling. Couples with it often describe breaking up and getting back together, or long gaps. It does well when both people want freedom; it strains when one wants routine.
Mars contacts: heat and fights
Mars squares to Mars, the Sun or Venus give energy, desire and arguments. Mars to Venus in a hard aspect is often wanted: many astrologers would rather see one than none, because it means attraction. Mars to Mars or Mars to Saturn in a hard aspect is harder: both want to lead, or one keeps braking. Fair rules for disagreement help more here than anywhere else.
House overlays people worry about
Aspects are only half of synastry. The other half is where each person's planets land in the other's houses. Two get the worst press:
- Their planets in your 12th house: the 12th is hidden things and loss. A partner's planets here can feel like a secret bond, a sense of losing yourself, or a feeling they see what you hide. It is not a sign of betrayal.
- Their Saturn or Pluto in your 8th house: intense, serious about money and intimacy; can feel controlling. The 8th house guide covers that house in full.
- Their Saturn in your 7th or your 1st: they feel like a duty or an authority; good for commitment, hard for ease.
Overlays need both birth times. Without them, read aspects only.
When a chart is lopsided
Astrologers worry less about one hard aspect than about a pattern:
- Many hard aspects to one person's Moon or Venus and few easy ones: that person may feel hurt more often.
- All the heavy planets one way: one person's Saturn and Pluto on the other's personal planets, and little going back. One person may feel they carry the weight or hold the power.
- No easy contacts between the lights (Sun and Moon): less natural understanding to fall back on.
Count tight contacts (under 3°) first. Ten wide hard aspects matter less than one exact one.
When a hard aspect is better than none
- A Venus–Mars square often gives more lasting attraction than no Venus–Mars contact.
- A Saturn contact, even a hard one, often comes with staying power; couples without any can drift.
- A Sun–Moon opposition is on many lists of marriage aspects: opposites that complete each other.
That's why reading a hard aspect as "avoid" misses most of the picture. The full order for reading two charts is in synastry chart interpretation.
What helps when your chart has hard aspects
- Name the pattern together. "When I go quiet, you hear criticism" does more than any chart.
- Look for the balancing contacts. Easy aspects between Sun, Moon and Venus give you somewhere to meet.
- Check the composite and both charts. A hard synastry contact can echo something already hard in one person's own chart; that part is theirs to work on, not the relationship's.
- Mind the timing. Transits to the touched planets make hard contacts louder for a while, then quieter.
- Get outside help when it's the relationship, not the chart. A couples counsellor works with what's happening; a chart only describes themes.
When it isn't about astrology
Hard aspects describe friction, not harm. If a partner controls your money, isolates you from friends, threatens you, or hurts you, that is not Pluto or Saturn: it's abuse, and it isn't yours to "work through". In the US, the National Domestic Violence Hotline is free and confidential at 1-800-799-7233, or text START to 88788. In an emergency, call 911.
A checklist for your two charts
- List every contact between Saturn, Pluto, Neptune or Uranus and the other's Sun, Moon, Venus or Mars, both ways.
- Mark the orb. Keep those under 6°; star those under 3°.
- List Mars–Mars and Mars–Sun squares and oppositions.
- List the easy contacts between Sun, Moon and Venus.
- Check which way the heavy contacts run: both ways or one way.
- With birth times, check 7th, 8th and 12th house overlays.
- Write one sentence for each starred contact on what it asks of you two.
A worked example
Partner A's Saturn is at 14° Capricorn. Partner B's Moon is at 12° Aries. That's a square, 2° from exact: a tight Saturn–Moon contact. B's Venus is at 10° Taurus, trine A's Saturn (4° orb), and A's Sun is at 8° Leo, trine B's Moon (4°).
- Hard: Saturn square Moon, tight. B may feel A is cool or critical about feelings; A may feel B is moody.
- Balance: Saturn trine Venus gives loyalty; Sun trine Moon gives natural understanding.
- Reading: a committed pair with one sore spot around emotional warmth. What helps: A says the kind thing out loud; B names needs rather than expecting A to read them.
Most of these contacts don't need a birth time; only the ones to the Moon and the Ascendant do. If one of you doesn't know your time, see synastry without a birth time for which ones to trust.
Mistakes when looking for aspects to avoid
- Writing a relationship off on one aspect. Most long couples have hard contacts.
- Using huge orbs. A "square" at 9° barely counts.
- Counting generational aspects. Your Pluto square their Neptune is shared with your whole age group.
- Reading only one direction. Check both people's planets to each other.
- Using Sun signs alone. Sun-sign compatibility is a start; the hard contacts above need full charts. For sign pairs, see the compatibility pages.
- Blaming the chart for behaviour. A chart can describe a pattern; it doesn't excuse one.
Frequently asked questions
What is the worst synastry aspect?
Saturn square or opposite the Moon is the one named most often, followed by hard Pluto–Venus, Pluto–Moon and Mars–Saturn contacts. None is a verdict on its own.
Can a relationship work with bad synastry?
Yes. Astrologers see many lasting couples with hard aspects. What they do with them matters more than how many they have.
Are squares bad in synastry?
Squares bring friction and also energy. A Venus–Mars square, for example, is often read as strong attraction.
Is Saturn bad in synastry?
No. Saturn is linked with both commitment and criticism. Easy Saturn contacts are among the best for staying power; hard ones need warmth on purpose.
Do I need birth times for synastry?
For aspects between planets, the dates are mostly enough (the Moon can be a few degrees off). For house overlays and the Ascendant, you need both times.
What about Sun sign compatibility?
It's a broad start. Full synastry looks at every planet, which is why two "incompatible" signs can do very well.
To check your own pair, get your free chart and your partner's, then run the checklist above. The guides page lists the rest of the synastry series.
Sources
- Astrodienst (astro.com), Astrowiki: "Synastry", "Aspect", "Orb". https://www.astro.com/astrowiki/
- Wikipedia, "Synastry" and "Astrological aspect". https://en.wikipedia.org/wiki/Synastry
- National Domestic Violence Hotline: 1-800-799-7233, text START to 88788. https://www.thehotline.org/
- Carlson, S. "A double-blind test of astrology." Nature 318, 419–425 (1985).
For entertainment.