Two hundred and twenty-five combinations, and astrologers do not learn them. They derive them, in three steps.
The combinatorial problem
Ten commonly used bodies produce forty-five possible pairings. Five major aspects applied to each gives 225 distinct configurations, before you add houses, signs or orbs.
Books exist that list them. Reading a chart from such a list is slow, produces disconnected sentences, and breaks the moment something unlisted appears.
Astrologers who can read charts fluently are not recalling entries. They are running a short procedure, and the procedure is learnable in an afternoon.
The three-step method
Step one: name both functions. Each planet supplies a verb, as covered in the article on what each planet signifies. Moon is instinct and need. Saturn is structure and limitation. Mercury is thought and speech. Venus is attraction and value.
Step two: decide the condition. Is this aspect effortless or effortful? Trines and sextiles indicate the two functions cooperate without friction. Squares and oppositions indicate friction between them. Conjunctions indicate fusion, with the character taken from the planets themselves.
Step three: combine. Describe how those two specific functions operate together under that condition. This is the step that requires thought, and it is where the reading actually lives.
Two guards to apply while doing this.
Keep both planets present. A common error is letting the more dramatic planet swallow the reading. Saturn conjunct Venus is not a Saturn placement, it is both.
State the cost and the use. Effortless configurations have a failure mode, usually neglect. Effortful ones have an advantage, usually development. A reading that only gives one side is half done.
Worked examples
The method applied, so the abstraction has something to hold onto.
Moon square Saturn. Functions: emotional need and instinct, against structure and limitation. Condition: friction. Combined: an emotional nature that meets restriction, where feeling and duty pull against each other. Astrologers read it as difficulty expressing need, a tendency to self-sufficiency, and, with work, considerable emotional durability. The cost is loneliness; the use is that the person can hold things others cannot.
Mercury trine Jupiter. Functions: thinking and communicating, with expansion and meaning. Condition: effortless. Combined: a mind that naturally reaches for the large picture, generous in expression, comfortable with abstraction. Read as an easy facility with learning and explanation. The failure mode is the trine's usual one: fluency that is never disciplined, and a tendency to overstate.
Venus conjunct Mars. Functions: attraction and value, fused with drive and assertion. Condition: fusion, and both are personal planets with appetite in common. Combined: wanting and pursuing operating as one motion. Read as directness in attraction and strong appetite. The cost is difficulty separating desire from action.
Sun opposite Moon. Functions: conscious identity against instinctive need. Condition: tension, experienced through others. Combined: a pull between what a person is becoming and what they already are. Anyone born near a full moon has this. Read as requiring balance between direction and need rather than resolution in favour of either.
Notice that none of those required a reference book, and that each one names both a difficulty and a use.
How this is taught inside Astra Trainer
This is Aspects between Planets, one of thirteen sub-topics in the Astrology direction of the Spiritual world.
It follows Aspects, which covers the geometry and orbs, and precedes Natal Chart Reading, where aspects are combined with placements into a whole. The direction teaches the derivation rather than tables, for the same reason it does with planets in signs. Lessons take about five minutes, and there is a discussion thread under every one.
Which planet leads
A convention that adds precision and is often omitted.
In traditional practice the slower planet is read as setting the terms, and the faster as the one that must adjust. The reasoning is mechanical: the faster body moves to meet the slower one, so the slower one is the fixed condition.
Taking Moon square Saturn again: Saturn is much slower, so Saturn sets the condition and the Moon operates under it. The reading is emotional need constrained by structure, rather than structure disturbed by feeling.
Reverse it and you get a different sentence with a different emphasis. Both describe the same aspect; the convention tells you which way round to say it.
The ordering by speed runs Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. The one further down that list sets the terms.
The aspects that cannot happen
A constraint that is astronomical rather than interpretive, and it is useful to know.
Mercury and Venus are interior planets. From Earth they never appear far from the Sun.
Mercury stays within roughly 28 degrees of the Sun. So Mercury can be conjunct the Sun, and cannot form a sextile, square, trine or opposition to it. Anyone offering a reading for Mercury opposite Sun is describing something that does not occur.
Venus stays within roughly 48 degrees. So Venus can be conjunct or sextile the Sun, and never square, trine or opposite it.
Mercury and Venus stay close to each other for the same reason, which limits the aspects possible between them.
Two consequences worth drawing out.
It is a test of a source. A book or site listing Venus square Sun is not checking against the sky.
It explains why those conjunctions matter. The Sun, Mercury and Venus cluster in most charts, so their relationships are nearly always conjunctions, and the tradition developed specific distinctions about how close Mercury sits to the Sun as a result.
Patterns made of several aspects
When three or more planets connect, the tradition reads the configuration as a unit.
The grand trine. Three planets each 120 degrees from the others, usually all in one element. Read as a self-contained circuit of ease, and traditionally with the warning that it can be too self-sufficient to generate effort.
The T-square. Two planets in opposition, both square a third. The third planet takes the pressure of the opposition and is read as the focal point where the tension concentrates and where the work is.
The grand cross. Two oppositions at right angles, producing four planets in mutual squares. Read as considerable tension distributed across four points, demanding and, in the tradition's framing, productive of capability.
The yod. Two planets in sextile, both in a 150-degree relationship to a third. Read as an awkward configuration requiring adjustment, and treated with varying seriousness by different practitioners.
The reason to read these as units is that the parts constrain each other. In a T-square the focal planet cannot be read as simply squared twice, because it is holding an opposition apart, which is a different job.
Not a basis for decisions. This article describes how astrologers read relationships between planets within their own tradition. Astrology is not a source of medical, psychological, financial or legal guidance, and nothing here should inform decisions in those areas. For health concerns see a qualified medical professional, and for financial or legal matters a qualified professional in that field.
What to take from this
Two hundred and twenty-five combinations are derived rather than memorised, in three steps.
Name both functions, decide whether the condition is effortless or effortful, then describe how those two functions combine under it.
The slower planet sets the terms, which tells you which way round to phrase the reading.
Some aspects are astronomically impossible, and a source that lists Venus square Sun has not checked the sky.
And multi-planet patterns are read as units, because in a T-square or grand trine the parts constrain each other in ways the separate pairs do not capture.
How do I read an aspect without a lookup table?
Name what each planet does, decide whether the aspect is effortless or effortful, then describe how those two functions combine under that condition. Include both the cost and the use.
Which planet dominates in an aspect?
By convention the slower one sets the terms, because the faster body moves to meet it. The speed order runs Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
Can Venus be square the Sun?
No. Venus never appears more than roughly 48 degrees from the Sun as seen from Earth, so it can only be conjunct or sextile it. Mercury stays within about 28 degrees and can only be conjunct.
What is a T-square?
Two planets in opposition with both square to a third. The third is read as the focal point where the tension of the opposition concentrates, and it is read differently from a planet simply receiving two squares.
Is a grand trine purely fortunate?
Not in the tradition's own terms. It describes a closed circuit of ease, and the standard caution is that it can be too self-sufficient to generate the effort that develops capability.
