Astrology
Chart patterns
An aspect connects two planets. A pattern is what three or more of them make together, and the tradition gives those shapes names. This is what each one is, how it reads, and how often it actually turns up.
These numbers are counted, not guessed
Every share below comes from running the same detector this site uses over one chart per day from 1900 to 2100, which is 73,049 charts of real ephemeris. That was worth doing because the received wisdom turned out to be wrong: a yod is described almost everywhere as rare and fated, and it is more than twice as common as the grand trine that gets called lucky.
Three things the numbers depend on, all worth knowing before quoting them. They move with the orbs, so whether a chart “has” a grand trine is a question about the orb used rather than about the sky. They count ten planets and no angles, so an astrologer including your Ascendant and Midheaven will find more than this. And they are frequencies across moments rather than across people.
All eight, commonest first
| Pattern | Shape | Planets | Share of charts |
|---|---|---|---|
| Stellium | Three or more planets in one sign | 3 | 66.3% |
| T-square | Two planets opposite each other, both square a third | 3 | 23.3% |
| Yod | Two planets sextile, both quincunx a third | 3 | 11.1% |
| Grand trine | Three planets each 120 degrees from the other two | 3 | 5.2% |
| Kite | A grand trine with a fourth planet opposite one of its points | 4 | 2.4% |
| Mystic rectangle | Two oppositions joined by two trines and two sextiles | 4 | 1.1% |
| Grand cross | Two oppositions at right angles: four planets, four squares | 4 | 0.78% |
| Grand sextile | Six planets evenly spaced: six sextiles, six trines, three oppositions | 6 | once in 73,049 |
Built from hard aspects
Squares and oppositions. Read as demand and development rather than misfortune, which is both truer to the tradition and the only honest way to write them.
Built from soft aspects
Trines and sextiles. Read as ease, with the caution the tradition has always attached to it: a configuration that works without effort is one nobody has any reason to develop.
Built from both
Hard and soft together. These are the patterns the tradition tends to treat most favourably, because the tension supplies a reason to act and the flowing aspects supply a route.
Built from position, not angle
A claim about how much of the chart sits in one place. The only entry here that is not defined by an angle at all.
Which of these are in your chart?
The birth chart tool detects all eight and names them, along with the planet at the apex where there is one. It works on the same ten planets and the same orbs as the counts above, so what it finds and what this page says will agree.