Modern: 1 degree, and often half that. No traditional orb exists for it.
Class
Minor
Nature
Neutral
Keywords
Twentieth harmonicSemi decileFaint contactDetail
Meaning
One twentieth of the circle, the smallest angle in ordinary harmonic use. The vigintile is a faint contact: it marks a detail that recurs, and it is read only in aggregate, as a family of contacts at the same degree rather than as a single relationship. At this size the objection that the orb can swallow the angle is serious.