
Indigenous women participate in a Mayan ceremony marking the autumnal equinox.
Photograph by Luis Romero
John Roach for National Geographic News
September 23, 2011
Stars and planets are lining up for the change of seasons during the Northern Hemisphere's autumnal equinox—the first day of fall—which will happen in 2011 at 5:05 a.m. ET Friday.
As if to mark the first full night of fall, the bright star Arcturus will hang high above the point where the sun sets on September 23, said Alan MacRobert, senior editor of Sky & Telescope magazine in Cambridge, Massachusetts.
Off to Arcturus' right will be the Big Dipper, positioned so that its ladle-like shape appears upright to ground-based observers, with its bowl to the right and handle to the left.
Much more here:
http://news.nationalgeographic.com/news/2011/09/110923-autumnal-equinox-northern-hemisphere-first-day-fall-2011-science