The full moon is the most universally observed Esbat timing across Wiccan traditions, tied to the belief that magical working reaches peak effectiveness at that phase; some traditions add a working at the new or dark moon as well, oriented toward different kinds of magic, such as banishing or beginning new projects rather than the culminating work associated with the full moon. The word Esbat itself has an uncertain history: Gardner era writers derived it from an Old French term, but the etymology is not settled among historians of the movement and this atlas records that uncertainty rather than asserting a confident derivation.
Because Esbats occur far more frequently than sabbats and are often smaller, more intimate gatherings, published descriptions of them tend to describe general structure and purpose rather than a single fixed liturgy, and Starhawk's Spiral Dance treats the full moon working as a recurring anchor of Goddess centered practice rather than a single scripted event.
Practical almanacs and calendars published for a Wiccan and wider Pagan readership, a genre Cunningham's own body of work helped establish, typically list exact full moon dates and names for the year ahead, reflecting how thoroughly the Esbat calendar has become a standard reference tool for practitioners independent of any single coven's own record keeping.