Aspects in astrology are the angles between planets in a birth chart, measured in degrees around the 360-degree zodiac wheel. The five major aspects are the conjunction (0 degrees), sextile (60), square (90), trine (120) and opposition (180). Astrologers read each one as a kind of relationship between two planets: blending, cooperating, clashing or pulling in opposite directions.
If signs tell you what a planet is like and houses tell you where it acts, aspects tell you who it talks to. Here's what each aspect means, how much leeway astrologers allow, how to measure one yourself, and the patterns worth recognizing.
The five major aspects at a glance
These are often called the Ptolemaic aspects, after the second-century astronomer Ptolemy, who wrote about them.
| Aspect | Angle | Signs apart | Usual orb | Read as |
|---|---|---|---|---|
| Conjunction | 0° | Same sign | up to about 8° to 10° | Fusion: two planets act as one |
| Sextile | 60° | Two | about 4° to 6° | Opportunity, easy cooperation |
| Square | 90° | Three | about 6° to 8° | Friction that forces action |
| Trine | 120° | Four | about 6° to 8° | Natural flow and talent |
| Opposition | 180° | Six | up to about 8° to 10° | Polarity, balance, projection |
There's a neat logic to them. Signs that trine each other share an element, which is why the trine is easy: Aries, Leo and Sagittarius are all fire. Signs that square each other share a mode but not an element, cardinal fire against cardinal water for example, so they push in incompatible ways. Signs in opposition share a mode and sit across the wheel from each other. Sextiles link friendly elements, fire with air and earth with water. Our guide to zodiac elements and modalities covers the groupings.
How close counts: orbs
Planets rarely sit at exactly 90 or 120 degrees from each other. The orb is the leeway astrologers allow around the exact angle. A Sun at 10 degrees Aries and a Moon at 14 degrees Leo are 124 degrees apart: a trine with a 4-degree orb.
There's no single rule for orbs. Most astrologers allow wider orbs for the Sun and Moon and for the conjunction and opposition, and narrower ones for sextiles and the minor aspects. The tighter the orb, the stronger the aspect is said to be. An aspect within a degree is called exact, or partile, and is read as a defining feature of the chart.
Astrologers also ask whether an aspect is applying, with the faster planet still moving toward the exact angle, or separating, with the exact moment already past. Applying aspects are usually read as stronger.
How to measure an aspect by hand
The simplest method is to turn each position into a number from 0 to 360. Aries runs from 0 to 30, Taurus from 30 to 60, Gemini 60 to 90, and so on round to Pisces at 330 to 360.
Example one. Venus at 14 degrees Taurus is 30 + 14 = 44. Mars at 17 degrees Leo is 120 + 17 = 137. The difference is 93 degrees: a square, with a 3-degree orb. Venus moves faster than Mars, and it's 3 degrees short of the exact angle, so the square is applying. Read: attraction and desire that work through friction, sparks as well as arguments.
Example two. The Moon at 28 degrees Gemini is 88. Saturn at 1 degree Virgo is 151. The difference is 63 degrees: a sextile, with a 3-degree orb. But Gemini and Virgo are square signs, not sextile ones. This is an out-of-sign aspect. Many astrologers count it at full strength, while others read it as weaker or mixed, because the signs involved don't share the aspect's usual harmony.
If the difference comes out over 180, subtract it from 360. Planets 300 degrees apart one way are 60 degrees apart the other way. Our free birth chart draws every major aspect on the wheel and lists the closest ones, so you can check your arithmetic.
Why a square isn't bad news
Older books called squares and oppositions malefic and trines and sextiles benefic. Modern astrologers mostly avoid those words, for good reason.
A square is friction, and friction is how things move. A Sun square Mars may describe someone with a short fuse, but also enormous drive. A trine, by contrast, describes a talent that comes so easily it can go unused. Plenty of astrologers say the most accomplished people have challenging aspects they've learned to work with, and the most comfortable charts can be the least motivated.
So "hard" and "soft" are better words than "bad" and "good." Hard aspects (squares, oppositions, some conjunctions) bring tension and growth. Soft aspects (trines, sextiles) bring ease and flow. Most charts need both.
The minor aspects worth knowing
Beyond the five majors, astrologers use smaller angles, usually with orbs of only a degree or two. Johannes Kepler, the astronomer, proposed several of them, including the quintile, in the early seventeenth century.
- Semisextile (30°): neighboring signs; mild, a slight awkwardness.
- Semisquare (45°): half a square; irritation, low-level pressure.
- Quintile (72°): a fifth of the circle; associated with creative talent and skill.
- Sesquiquadrate (135°): a square and a half; tension that builds until it's dealt with.
- Quincunx, or inconjunct (150°): two signs with nothing in common, no shared element, mode or polarity. Read as constant adjustment, like two people who speak different languages.
The quincunx is the minor aspect astrologers mention most, and some treat it almost as a major one.
Aspect patterns to recognize
When three or more planets link up, astrologers name the shape:
- T-square: two planets in opposition, both square a third. The third planet, the apex, is where the tension discharges. A very common, very dynamic pattern.
- Grand trine: three planets trine each other, usually all in one element. A closed loop of talent and ease, which can make it hard to get going.
- Grand cross: four planets forming two oppositions and four squares, usually all in one mode. Rare, intense and hard-working.
- Yod: two planets sextile each other, both quincunx a third. Sometimes called the Finger of God; read as a sense of mission at the apex planet.
A stellium, several planets in one sign, isn't an aspect pattern as such, but it's made of conjunctions and often joins in with one.
Aspects also work between two people's charts. When one person's Venus trines the other's Mars, that's synastry. Our guides to what synastry is and Venus and Mars aspects in synastry take it from there. To have your own aspects read in the context of the whole chart, the natal chart report covers them in full.
Questions readers ask
Which aspects are the most important?
The five majors, especially conjunctions and the hard aspects, along with any aspect within a degree or two. Aspects involving the Sun, Moon, Ascendant or the planet that rules your rising sign usually carry the most weight.
What is the difference between a square and an opposition?
A square (90 degrees) is friction between planets that want different things, pushing for action. An opposition (180 degrees) is a tug-of-war between two ends of one axis, often felt through other people, and calls for balance.
Do aspects to the Ascendant and Midheaven count?
Yes. Planets aspecting the Ascendant shape how you come across; planets aspecting the Midheaven shape your public direction. Both need an accurate birth time.
Is a chart with no squares easier?
Not necessarily. A chart with few hard aspects can be comfortable but under-motivated. Many astrologers see a mix of tension and ease as the healthiest combination.
