What an aspect actually is
Take the circle of the zodiac. Put two things on it — two planets in one chart, or two people's Sun signs. Measure the angle between them. That angle is the aspect, and it is the oldest measurement in astrology: it is geometry, not symbolism, and everything symbolic is attached afterwards.
Only certain angles count, and the selection is not arbitrary. They are the divisions of the circle by small whole numbers: 360 divided by one, two, three, four, six and twelve. That is the conjunction, the opposition, the trine, the square, the sextile and the semi-sextile. The quincunx at 150° is the odd one out — it is not a clean division of the circle, and its awkwardness in the arithmetic is the reason for its reputation.
Why the angle decides the element
This is the part that is usually presented as three independent facts and is really one. On a twelve-sign wheel, the distance between two signs determines their element and their mode. Signs four apart always share an element. Signs three apart always share a mode. Signs six apart are always the same polarity.
So “they are both fire signs”, “they are both cardinal” and “they are four signs apart” are not three pieces of evidence. They are one piece of evidence stated three times. A compatibility model that adds them together is counting the same thing repeatedly, and the result is that every pairing comes out flattering and the scores collapse into a narrow band — which is exactly what happened to the first version of this site's engine, and why it was rebuilt around the angle alone.
The seven, one at a time
☌ Conjunction — 0°, 0 signs apart
The conjunction is the only aspect with no fixed character, because its character is whatever the two bodies are. Sun with Jupiter is not Sun with Saturn. The consistent part is the fusion: from the inside it is very hard to tell where one ends and the other begins, which is why a conjunction is usually the last thing a person notices about their own chart. Between two people's Sun signs it means the same sign twice — a rare draw, and the hardest one to see clearly, because a shared fault is a fault neither party is positioned to notice.
⚺ Semi-sextile — 30°, 1 sign apart
Adjacent signs share nothing: not element, not mode, not polarity. They are simply next to each other, which turns out to be the least useful relationship two positions can have. The semi-sextile produces low-grade, persistent friction that never escalates into a proper argument and never resolves either — the sort of difference that gets restated more slowly, at greater length, with no effect whatsoever. It is given a narrow orb because at any real distance it stops registering at all.
⚹ Sextile — 60°, 2 signs apart
Sixty degrees apart puts two signs in compatible elements — fire with air, earth with water — and the traditional reading is opportunity rather than gift. The sextile is easy but not automatic: it offers, and something has to accept. That is the whole difference between it and the trine, and it is why the sextile ages better. A trine can go unexamined for thirty years; a sextile that nobody uses simply stays a door.
□ Square — 90°, 3 signs apart
Signs ninety degrees apart share a mode and nothing else: two cardinal signs both want to start, two fixed signs both refuse to move first, two mutable signs both bend and nothing gets anchored. That shared mode is exactly what makes the square grind — the two positions want the same kind of thing and go about it in incompatible elements. It is also, by a wide margin, the most productive hard aspect. Squares are where things actually get built, because nothing here resolves by being ignored.
△ Trine — 120°, 4 signs apart
A hundred and twenty degrees puts two signs in the same element, which is the closest thing the wheel has to a shared native language. The old astrologers called this angle fortunate and did not trouble themselves to explain why. The modern caveat is worth adding: trines go soft. What arrives this easily gets taken for granted, and a chart with many trines and no squares tends to describe someone with real gifts and no particular reason to have developed them.
⚻ Quincunx — 150°, 5 signs apart
Also called the inconjunct, and it is the strangest aspect on the wheel: no shared element, no shared mode, no shared polarity, and not the clean opposition either. There is no common ground of any kind, so the relationship is one of permanent adjustment — each side keeps aiming at where it assumes the other is standing and keeps missing by the same margin, and the margin feels like carelessness rather than like geometry. It is the lowest-scoring angle in the reading this site produces, and it is also the most interesting one.
☍ Opposition — 180°, 6 signs apart
Opposite signs share a mode and sit in complementary elements — fire opposite air, earth opposite water — so an opposition is not a mismatch. It is a see-saw. Each end is genuinely real and standing on one denies the other, which is why the classic opposition behaviour is projection: the quality that drew you in is the quality you will later criticise, in almost the same words, in a different tone. It scores well above the square here precisely because both ends are legible; nothing about an opposition is mysterious, it is just tiring.
All seven, side by side
| Aspect | Angle | Distance | Family | Weight | In one line | |
|---|---|---|---|---|---|---|
| ☌ | Conjunction | 0° | 0 signs | neutral | 76 | Two bodies in the same place. They do not take turns; they arrive as one impulse. |
| ⚺ | Semi-sextile | 30° | 1 sign | hard | 50 | Neighbours on the wheel. Near enough to touch, too near to focus on. |
| ⚹ | Sextile | 60° | 2 signs | soft | 83 | An open door neither party remembers building. |
| □ | Square | 90° | 3 signs | hard | 44 | Friction with no natural release. The same disagreement, in new costumes. |
| △ | Trine | 120° | 4 signs | soft | 93 | Flow. It works without being asked, which is why it is rarely examined. |
| ⚻ | Quincunx | 150° | 5 signs | hard | 36 | The blind angle. Nothing lines up, and something keeps both parties in the room. |
| ☍ | Opposition | 180° | 6 signs | hard | 67 | Across the wheel. The pull that does not weaken with distance. |
Orbs: how close is close enough
An aspect is rarely exact. A square at 87° is still read as a square, and the distance from exactness is called the orb. How much orb to allow is a matter of school rather than of fact: wide orbs find more aspects and dilute them, narrow orbs find fewer and mean more.
This site works at whole-sign resolution, so the two-person reading has no orb at all: two signs are either four apart or they are not. Orbs start to matter the moment you are placing real planets at real degrees, which is a full chart rather than a Sun-sign reading — where this site stops is set out here. Conventional middle-of-the-road values are eight degrees for a conjunction or opposition, six for a square or trine, four for a sextile, three for a quincunx and two for a semi-sextile, usually with a couple of degrees extra when the Sun or Moon is involved.
How this site uses them
The two-person reading takes the angle between two Sun signs, weights it by the traditional value in the table above, and then adjusts it by the angle between the two faces — the ten-degree thirds of each sign. That second term is what stops every Aries-and-Leo pairing on earth returning one identical number.
The group reading uses the same seven angles across up to eight people at once — twenty-eight pairs — and reports the shape of all of them rather than any one.