The classical aspects

What it is

An aspect is a relationship of regard between two of the seven planets, and Ptolemy sets it by the signs the planets occupy, not by their exact degrees. Two bodies are configured when their signs stand in one of a small, fixed set of whole-sign relationships. Because every sign is a full thirty degrees wide, the relationship exists the moment the planets fall in the right pair of signs, whatever their precise longitudes.

There are five, counted by how many signs separate the two places: the conjunction (one shared sign), the sextile (two signs), the square (three), the trine (four), and the opposition (six). Every remaining separation, of one sign or of five, forms no aspect at all; those places are averse, strangers that cannot behold each other.

This is why the classical scheme admits no minor aspects. The thirty-degree and one-hundred-and-fifty-degree distances that a later astrology treats as faint contacts are exactly the two aversions, and an aversion is the absence of a configuration, not a weak one. The degree a planet holds within its sign is not discarded, but it only refines a bond the signs have already made. Sign first, degree second.

How the tradition computes it

The five configurations follow from the sign-count. Ptolemy names four in the chapter on mutual configurations, deriving each by dividing the semicircle into halves and thirds; the conjunction he treats apart, since a place cannot be configured with itself, though its power is described throughout the later chapters. The app counts it the fifth. Their glyphs and sign-distances:

Signs one apart (thirty degrees) or five apart (one hundred and fifty degrees) share no familiarity and produce no aspect; Ptolemy classes them as inconjunct. An aversion is therefore not a configuration to be measured with an orb, but simply a pair of places that do not regard each other.

Applying and separating

Within a configuration, the faster of the two bodies decides the direction of the contact.

the planet which precedes is said to apply to that which follows (Tetrabiblos I.27)

When the swifter planet is closing the exact angle the aspect is applying, and its effect is gathering; once it has passed the angle and is drawing away the aspect is separating, and its effect is spent. For a bodily conjunction the latitudes are weighed too, so that only a true meeting in the same part of the zodiac counts; for the other aspects the rays converge alike from every quarter.

Partile, platic, and the orbs

A contact exact to within a single degree is partile; a wider one, still within reach, is platic. Reach is set by the orbs. Each body carries a full orb, and its moiety is half of that. The effective orb between two bodies is the sum of their two moieties:

effective orb = orb(A) / 2 + orb(B) / 2

A whole-sign contact that runs wider than about eight degrees is read by sign only, its degree-strength set aside while the configuration itself still stands. Aspects also carry a hand: a dexter ray is cast against the order of the signs, toward an earlier sign, and a sinister ray is cast with the order, toward a later one; the dexter is reckoned the stronger.

The Sun's phases, a power apart

Nearness to the Sun is not an aspect but a separate condition of a planet, measured by plain distance in longitude. Within roughly a quarter-degree of the Sun a planet is cazimi, in the heart of the Sun, a great strengthening; within eight degrees it is combust, a burning; within fifteen degrees it is under the beams, a dimming.

What it signifies

An aspect is a channel through which the natures of two planets, their heat and cold, moisture and dryness, mix and modify one another. The kind of sign the configuration falls across decides whether that mixing is easy or strained. Trine and sextile are harmonious, joining signs of the same kind, all masculine or all feminine; square and opposition are discordant, joining signs of different natures and sexes, which pull against each other.

The planets colour the result. A trine or sextile from Jupiter or Venus, the benefics, tempers and warms; a square or opposition from Mars or Saturn, the malefics, heats to excess or chills and dries. A conjunction blends two natures in one place directly, for good where a benefic is present and for harm where a malefic burns. Application makes the effect gather force; separation means it is passing off. An aversion signifies indifference: the two places neither help nor hinder, because they cannot see each other at all.

Where the app departs

Seen in a real chart

In the chart of Marcus Aurelius the tightest applying aspect is Venus trine Jupiter, at 1.9° applying. Venus sits in Pisces in the first house, exalted and the chart lord; Jupiter sits in Scorpio in the ninth, retrograde and in its term. Pisces and Scorpio stand four signs apart, so the trine exists by sign, and the 1.9° then refines it. Venus, the swifter body, is still closing, so the aspect is applying, a benefic trine gathering strength. Their moieties, four degrees for Venus and six for Jupiter, give a ten-degree effective orb, so at 1.9° the contact sits well within reach, tight but not yet partile.

Aversion is easier felt than found here: all seven planets fall in feminine signs, so no two of them are averse, and each regards every other. But the Midheaven sign, Sagittarius, is masculine, and the Sun in Taurus stands five signs from it, in aversion to the tenth place. For the Sun's phases, Mars gives the plain case: it lies 4.1° from the Sun, inside the eight-degree orb, and so is combust, the lesser malefic scorched by the beams.

How to read it in the app

The natal reading lists each configuration by its sign-distance, marks it applying or separating with the degree of application, and flags a wide contact as read by sign only, so you can tell a partile bond from a merely present one at a glance. The citation footnote beneath the aspect list resolves to Tetrabiblos I.16 and I.27.

Sources