Trine

The trine is an aspect of one hundred and twenty degrees, formed when two planets stand a third of the circle apart. It is one of the five major, or Ptolemaic, aspects and the most harmonious of them all, the chief of the soft aspects. One hundred and twenty degrees links signs of the same element, fire with fire, earth with earth, and so on, so the planets involved blend with complete sympathy, and the tradition reads the trine as flow, ease, talent, and good fortune given freely. Some modern astrologers caution that its very ease can incline to complacency, the gift that is never worked for. It is allowed one of the larger orbs. These are the interpretive conventions of the astrological tradition for this angular relation, in which the trine represents the smoothest and most favourable connection two planets can make.

The trine's near-universal reputation for ease rests on its being the aspect of shared element, fire with fire, earth with earth, water with water and air with air, so that the two signs involved belong to the same triplicity, the ancient grouping Ptolemy uses throughout the Tetrabiblos to classify temperament and season. Because the relation is symmetrical and the element identical, Hellenistic astrologers such as Vettius Valens, writing around 175 CE, did not apply to the trine the directional overcoming they used for the square, since neither planet stands in a position of advantage over the other. The modern caution that ease invites complacency is a twentieth-century psychological gloss with no ancient precedent; older sources, including Ptolemy, simply rank the trine the most fortunate of the five figures and note, more practically, that a trine between two malefics still delivers its harm smoothly rather than sparing the chart from it.

A third of the circle is one hundred and twenty degrees, and three signs of the same element stand at that distance from one another. Fire trines fire, earth trines earth, air trines air, water trines water. The trine and the elemental scheme are therefore not two separate doctrines that happen to agree; they are one arrangement of the zodiac seen from two directions. This is worth stating because it explains why the trine was never controversial. It falls out of the structure rather than being imposed on it.

Ancient sources rank the trine as the most favourable of the configurations, and the reason given is geometric rather than sentimental: it joins signs that share a nature, so the planets involved are not asked to reconcile anything. The opposition joins signs of contrary nature, the square joins signs that share a mode but not an element, and the trine joins signs that agree throughout. Hellenistic writers use the term for it that also means agreement.

The modern addition is a caution rather than a technique. Nineteenth and twentieth century writers began to treat the trine as a place where nothing is demanded and therefore nothing is developed, an ease that can become inertia. That reading has no ancient warrant and should not be presented as though it did, but it is now common enough that a reader encountering a chart discussion of trines will meet it. Orbs for the trine are generally set wide, on both the traditional planetary system and the modern aspect-based one, which makes it one of the aspects least affected by which convention a practitioner follows.

The trine belongs to the Hellenistic aspect doctrine given its lasting theoretical form by Ptolemy, its geometry that of the threefold division of the circle, and its glyph is an equilateral triangle, the same figure a compass and straightedge produce by stepping off three equal arcs. Unlike the conjunction, opposition and sextile, the trine's sign was never given a dedicated astrological codepoint of its own when the Unicode Standard was built; it is instead typically rendered with the ordinary geometric character for a triangle, WHITE UP-POINTING TRIANGLE at U+25B3, a shape borrowed wholesale from mathematical typesetting rather than purpose built for astrology, much as the square aspect reuses a plain geometric square.

The glyph itself is old: triangular aspect marks appear alongside the other aspect and planetary signs in the medieval Byzantine codices that preserve Hellenistic Greek horoscopes, and the shape was carried through largely unaltered as astronomical tables moved into print during the Renaissance, needing no further stylisation, since a triangle drawn quickly by hand and a triangle set in type differ hardly at all. That plainness sets the trine apart from the conjunction, opposition and sextile, whose marks had to be distinguished from ordinary geometric figures and so were given purpose-built forms and, eventually, purpose-built codepoints, while the trine and the square could simply borrow shapes mathematics had already fixed.