Sextile

A sextile is the aspect of sixty degrees, one of the five classical aspects. Traditionally it is counted among the harmonious or easy relationships between two bodies, though a milder and more effortful one than the trine. It is one of the four configurations Ptolemy treated as a genuine aspect in the strict sense of the Tetrabiblos, bodies two signs apart being close enough to behold one another clearly while sharing only a partial rather than a complete compatibility of element and quality, which is why tradition reads the sextile as opportunity that must be taken up rather than as ease that arrives on its own.

The sixty-degree arc inscribes a regular hexagon in the circle, and aspect doctrine of this kind was already established practice among Hellenistic astrologers before Ptolemy gave it systematic form; his real contribution to the sextile, as to the other three genuine aspects, was less to discover the relationship than to fold its recognised effects into a single causal account grounded in the elements and the qualities governing each sign. Signs sixty degrees apart share the same polarity but differ in element, a partial rather than a complete agreement, and later commentary has generally traced the sextile's reputation as a weaker, more effortful good aspect than the trine directly to that half measure of compatibility.