← Encyclopedia of Astrology · lesson 95/235
Trine
A trine is two planets 120° apart — a third of the circle, the third harmonic. It normally joins signs four apart, which share an element: Aries, Leo and Sagittarius in fire; Taurus, Virgo and Capricorn in earth; Gemini, Libra and Aquarius in air; Cancer, Scorpio and Pisces in water. Ptolemy counted it among the harmonious aspects, because the signs it joins are of one kind.
Its character is flow. The two planets understand each other and cooperate without effort: a trine shows where something comes naturally — a gift, a knack, a way of being that needs little practice. That ease has a familiar shadow, which Donna Cunningham and many others point out: what comes easily is easily taken for granted, and a trine may support a person without ever pushing them to use it.
Orb
A trine is a major aspect, and most astrologers give it room close to the opposition's: often 6–8°, more with the Sun or Moon, with traditional authors working from each planet's own orb. In the charts here the allowance comes from the two bodies — 8° for the Sun and Moon, 7° for the Ascendant and Midheaven, 6° for the other planets and the nodes, 2.5° for asteroids — taking the tighter of the pair. Its strength is how tight it is against that allowance, 1 at exact and 0 at the edge. See orb.
Ease or tension
The trine counts as ease in the ease and tension chart, a little below the full weight of the conjunction and opposition. Ease means support and opportunity rather than guaranteed good fortune; a trine inclines toward things going smoothly, and it still helps to act on it.
In a chart
Ask what the two planets give each other, and in which element. A trine between the Moon and Saturn might show a steady, dependable emotional life; between Mercury and Uranus, a quick and inventive mind. Three planets in mutual trine make a grand trine, a closed circuit of talent; add a planet opposite one corner and it becomes a kite, which gives the talent a direction.
In transit
Trines in transit tend to open doors rather than force them: a period when something is easier to start, mend or enjoy. Because they rarely press, they are easy to miss — a trine is a good moment to do deliberately what the planets favour.
Kinds and conditions
- Applying trines are building; separating ones are fading.
- An out-of-sign trine joins signs of different elements — say 29° Cancer to 1° Sagittarius — and loses some of the shared nature that makes a trine easy.
- Exact trines are the strongest.