A chart is not a list of planets in signs. The planets see each other — or fail to see each other — and the geometry of those relationships is what turns a list of placements into a story. In Hellenistic astrology, the geometry is called configuration (Greek schēmatismos), and the relationships themselves are called aspects — literally, “lookings.”
Five classical aspects shape the chart: conjunction (0°), sextile (60°), square (90°), trine (120°), and opposition (180°). All five share a defining feature in the Hellenistic frame: they are relationships between signs, not just degrees. A planet in Aries aspects every other planet in any sign that Aries aspects — Gemini and Aquarius by sextile, Cancer and Capricorn by square, Leo and Sagittarius by trine, Libra by opposition. This is the whole-sign aspect doctrine, and it is the primary lens through which Hellenistic astrology reads the chart.
Beyond the five aspects there is a sixth condition — aversion — and several technical relationships built on top of the aspect structure: overcoming and dominion, bonification and maltreatment, and reception. Each is briefly treated below.
Conjunction (0°)
Two planets in the same sign are in conjunction. Strictly, the word aspect does not apply to two planets that occupy the same place — they are not so much looking at each other as standing on the same spot. But for practical purposes, the conjunction is the most intense of the configurations. Two planets in conjunction blend their natures; whatever each one signifies is colored by the other.
The character of a conjunction depends almost entirely on the planets involved. Two benefics — Venus with Jupiter — is among the most fortunate configurations in the tradition. Two malefics — Mars with Saturn — is among the most demanding. A benefic with a malefic is a mixed picture, often with the benefic mitigating the malefic and the malefic complicating the benefic.
The Sun with another planet is a special case. A planet within about 8° of the Sun is combust, its nature obscured by the Sun’s brightness; the planet still signifies, but it does so from inside an experience rather than from a clear vantage. A planet within roughly 15° but outside the inner band is under the beams, partially obscured. A planet exactly with the Sun, within about 17 minutes of arc, is cazimi — in the heart of the king — and is unusually empowered, the rare case in which proximity to the Sun strengthens rather than obscures.
Sextile (60°)
Two signs that are two signs apart form a sextile. The aspect is harmonious by classification — easy, supportive, friendly — though milder in its effect than the trine. Sextiles connect signs of complementary genders: a fire sign with an air sign, an earth sign with a water sign.
A sextile between two planets allows them to cooperate without strain. Benefics in sextile to each other, or to the lights, signify a smooth flow of their respective goods. A malefic in sextile to a benefic is somewhat softened. A sextile between two malefics is mild but still gives each malefic an opportunity to amplify the other’s themes by the easier route.
Square (90°)
Two signs that are three signs apart form a square. The aspect is difficult by classification — hard, abrasive, generative of friction. It is the strongest of the difficult aspects after the opposition, and in some technical contexts (overcoming, see below) it is the most consequential of all. Squares connect signs of the same gender but different elements: a fire sign squares earth and water, an air sign squares earth and water as well.
A square between two planets signifies that their natures meet at right angles — they cannot ignore each other and they cannot easily cooperate. Squares between benefics are not particularly bad; they signify that the goods of each must be reconciled with the other through some effort. Squares between malefics, or between malefics and the lights, are among the most demanding configurations in the chart and ask the closest reading of sect, condition, and reception.
Trine (120°)
Two signs that are four signs apart form a trine. The aspect is harmonious by classification — easy, generous, free-flowing — and signifies the most cooperative of the relationships between two planets. Signs that share an element (the fire signs Aries-Leo-Sagittarius, the earth signs Taurus-Virgo-Capricorn, the air signs Gemini-Libra-Aquarius, the water signs Cancer-Scorpio-Pisces) are in trine to each other.
A trine allows two planets to give their gifts to each other without resistance. Benefics in trine, especially to the lights, are among the most fortunate signatures in any chart. Even malefics in trine to benefics tend to soften considerably; the trine is the configuration most capable of bringing a malefic into a cooperative register. A malefic-to-malefic trine is still a stress, but it is a stress that often produces durable work — Saturn trine Mars can signify an athlete’s discipline or a craftsman’s perseverance, depending on the rest of the picture.
Opposition (180°)
Two signs that are six signs apart form an opposition. The aspect is difficult by classification — confrontational, polarizing, generative of pull — though differently from the square. Where the square brings two natures into friction, the opposition stretches them across the whole chart, each pulling against the other.
An opposition between two planets signifies a relationship in which neither can be reconciled to the other except through some third term — through some element that holds the two ends together. Oppositions involving malefics are among the most demanding configurations in the chart, especially when angular. Oppositions between benefics are not particularly bad; they signify two goods that must each be honored without sacrificing the other — Venus opposite Jupiter, for instance, can signify a tension between intimate love and broader vocation, both of which are real and both of which must somehow be lived.
Aversion
When two signs form none of the five aspects above, they are in aversion to each other — literally turned away. The relationship is not difficult; it is absent. Two planets in aversion do not see each other. Whatever each does in the chart proceeds as though the other were not there.
This is a more important condition than it sounds. A planet in aversion to its own domicile sign — for instance, a planet whose ruler sits in a sign averse to it — is a planet without good help available. A significator in aversion to the Ascendant means the topic it governs is hard to bring into the native’s clear view. A natal Moon in aversion to her ruler is a Moon without easy support.
The averse relationships are: one sign apart (e.g., Aries to Taurus, the semi-sextile in modern terminology), five signs apart (e.g., Aries to Virgo, the quincunx or inconjunct), and seven signs apart in certain counts. In whole-sign aspect doctrine, two planets in any of these arrangements simply do not aspect each other — they are not in difficult relationship; they are in no relationship at all.
Overcoming and Dominion
In the classical scheme, the right-side square — the square that approaches a planet from the sign in front of it in the order of the zodiac — is called the overcoming square. A planet in the tenth sign from another planet overcomes it, in the technical language. This is the strongest position for one planet to take over another, especially when the overcoming planet is a malefic.
Similarly, a planet in the eleventh sign from another (a right-side sextile) is in a position of partial dominion. The directions matter: aspects coming from one side of the chart are not always equivalent to aspects coming from the other.
For a chart reader, the practical upshot is to pay particular attention to which malefic is overcoming what — a Saturn in the tenth sign from a benefic is making serious work for that benefic, more so than a Saturn in some other configuration with the same benefic. The technique sounds technical, but its effect on a reading can be dramatic; a benefic that looks well-placed by one set of considerations may turn out to be heavily overcome by a malefic in the other.
Bonification and Maltreatment
Two planets in aspect can act on each other in multiple ways. Bonification is the cluster of conditions under which a benefic helps another planet — by aspect, by reception, by domicile lord. Maltreatment is the cluster of conditions under which a malefic harms another — by aspect, by enclosure (when the planet sits between two malefics by sign), by reception in difficult dignities.
The technical detail of bonification and maltreatment is one of the most precise instruments in the Hellenistic toolkit. A malefic in a difficult aspect to a benefic is one thing if the benefic has independent help; it is another thing entirely if the benefic itself is under maltreatment by a different malefic. The nuance of these chained conditions is a great deal of what makes a Hellenistic reading careful rather than abstract.
Reception
Reception is the relationship between a planet and the planet that rules its sign. A planet in Cancer is received by the Moon, since the Moon rules Cancer. The reception can be by domicile (the strongest), by exaltation (the second strongest), by triplicity, by bound, or by decan — each layer of dignity creating a particular kind of welcome.
When two planets are in mutual reception — each in the other’s domicile, for instance — they have a special relationship; even at a difficult distance, they support each other. Reception is one of the conditions that softens an otherwise difficult configuration. A malefic difficult by aspect but well received by a benefic is not the same as a malefic with no such reception.
A chart’s configurations are what turn its placements into a coherent reading. A list of planets in signs and houses is a vocabulary; the aspects are the syntax — the part that shows what each piece does to and with the others. Reading them well is largely a matter of patience: looking at each planet, asking whom it sees and whom it does not, and listening for what the geometry says about the relationships embedded in a life.