The exact time of the Autumn Equinox is September 23, 2011 at 3:09 am UTC but if you are in the US on the east coast then it will occur on the evening of September 22nd according to timeandate.com.
The Autumn equinox signals the beginning of Fall. It is the point where there is exactly 12 hours of daylight and 12 hours of darkness at the equator. The daylight hours are dwindling and will continue to do so until we reach the Winter Solstice, the shortest day of the year and the start of winter.
In ancient times, the Autumn Equinox was cause for a variety of pagan festivals, among them the celebration of the birth of Mabon, the son of Mordon, the Goddess of the earth.
It is also a time to celebrate with a variety of Fall and Harvest Festivals. People enjoy fall festivals as they sense the closure of a great summer season and the coming of a long winter. The fall festivals are the last of the outdoor events until spring. Just getting there is half the fun as you drive through hills and forests ablaze in fall color. So, get out and enjoy them.
Much LoVe and Gratitude