Which day is really the most correct for the celebration of the Autumnal Equinox/Mabon holiday:
...the night before the astronomical point of equinox?
...the next day/night?
...whichever is closest to the astronomical point?
...the day/night when day and night are actually equal where you live?
...the last day that the sun is in Virgo?
...the first day the sun is in Libra?
...whenever people around you are celebrating?