September 23rd, the Autumn Equinox. To Celts – this is the Second Harvest, when the ripe Acorns fall from the wild Irish Oaks and we plant them in fertile soil. This wonderful time is the time when day and night are equal in length. Equinox meaning “equal night”. In Ireland there is an ancient Irish equinox temple at Knowth, near Newgrange (Brú na Boinne). Knowth has a 100-foot long passage that only is light by the Sun on the morning of the Spring and Autumn Equinox.