Septile

A septile is the aspect of about fifty-one and a half degrees, a seventh of the circle, more precisely fifty-one degrees and twenty-six minutes, since a seventh of three hundred and sixty does not resolve into a whole number. It is a harmonic aspect that came into wider use with twentieth-century harmonic astrology, and unlike the quintile, biquintile and sesqui-quadrate it does not descend from Johannes Kepler's seventeenth century reform, since sevenfold division does not correspond to any of the constructible polygons and consonant musical intervals his argument in the Harmonices Mundi relied on. Its modern use is generally traced instead to the harmonics movement developed in Britain by John Addey, born in 1920 and the author of Harmonics in Astrology, published in 1976, which proposed reading whatever numerical divisions of the circle a chart emphasised, regardless of whether the resulting angles fit the twelvefold zodiac.

Because a seventh of the circle is an irrational fraction of a degree, the septile is read as a marker of the fated, the compulsive and the inspired, effects that resist ordinary measurement in the way its own angle does. Addey's harmonics approach treated the septile as one instance of a general method rather than a curiosity on its own, arguing statistically that certain numerical divisions of the circle recurred often enough in the charts of people sharing a profession or trait to be worth studying regardless of whether they had been part of any older astrological tradition.