Sextile

Ptolemy established the sextile as one of his five major aspects in Tetrabiblos (c. 150 CE), describing signs in sextile as regarding one another in a friendly manner. The sextile spans two signs — for example, Aries to Gemini, or Taurus to Cancer — and typically links signs of compatible but not identical elements (fire with air, earth with water). This structural compatibility produces an ease of communication between the two planetary energies involved. Unlike the trine's effortless flow, the sextile carries a mild productive tension that benefits from initiative. Robert Hand (Horoscope Symbols, 1981) characterized sextile opportunities as requiring conscious action to be realized: the door is open, but you must walk through it. William Lilly (Christian Astrology, 1647) used the sextile as a positive testimony in horary readings, indicating that the matter showed promise and the relevant parties were favorably disposed toward each other. In natal chart interpretation, a sextile between two planets indicates a talent or resource that can be developed — less automatic than a trine, more constructive than a square. The traditional orb for a sextile is approximately 4°–6°.