Mabon – Fall Equinox – The Season of Closure by Silver RavenWolf copyright 2016 The power of Mabon unfolds when the Sun is at 1 degree Libra. This year, Mabon (Fall Equinox) occurs on Thursday, the 22nd of September at 10:21 AM EDT/ 7:21 AM PDT. A few hours earlier, Mercury turns direct. The third quarter Moon is in Gemini in Her Disseminating (Harvest) phase. The Corn Mother, whether she is called Selu, Demeter, Brighid, the Cailleach, or Maighdean-Bhuana rules the Autumn Equinox.