First Day Of Autumn
Autumn Equinox On The 23rd September 2011
The Autumn Equinox is celebrated on the 22nd/23rd September in the northern hemisphere, and the 20th/21st of March in the Southern Hemisphere. At this time the Sun is directly overhead at the equator and day and night are of approximately equal lengths. At equinox, the Sun rises everywhere on Earth (except the Poles) at about 6am in the morning and sets at about 6pm in the evening (though this can vary a little when time zones and daylight saving etc are taken into account).
NB: At the North Pole the Autumn Equinox is effectively the Polar sunset whilst the South Pole experiences it as a Polar sunrise.
Also known as the September equinox, the event signifies the first day of autumn in the UK. The autumn equinox is also used to determine the date of the traditional harvest festival which is held on the first Sunday after the first full moon following the autumn equinox.
After this celebration the descent into winter brings hours of increasing darkness and chiller temperatures. It is the time of the year when night conquers day.
After the Autumn Equinox the days shorten and nights lengthen. To astrologers this is the date on which the sun enters the sign of Libra, the scales, reflecting appropriately the balanced day and night of the equinox.
The exact time for the Autumn (or Vernal) equinox at Stonehenge 2011 is:
Friday September 23rd 2011 @ 10:04 BST