Watch out for the Super Harvest Moon – NASA Science
Sept. 22, 2010: For the first time in almost 20 years, northern autumn is beginning on the night of a full Moon. The coincidence sets the stage for a "Super Harvest Moon" and a must-see sky show to mark the change of seasons.
The action begins at sunset on Sept 22nd, the last day of northern summer. As the sun sinks in the west, bringing the season to a close, the full Harvest Moon will rise in the east, heralding the start of fall. The two sources of light will mix together to create a kind of 360-degree, summer-autumn twilight glow that is only seen on rare occasions. …
Northern summer changes to fall on Sept. 22nd at 11:09 pm EDT. At that precise moment, called the autumnal equinox, the Harvest Moon can be found soaring high overhead with the planet Jupiter right beside it. The two brightest objects in the night sky will be in spectacular conjunction to mark the change in seasons. …
Usually, the Harvest Moon arrives a few days to weeks before or after the beginning of fall. It’s close, but not a perfect match. The Harvest Moon of 2010, however, reaches maximum illumination a mere six hours after the equinox. This has led some astronomers to call it the "Harvestest Moon" or a "Super Harvest Moon." There hasn’t been a comparable coincidence since Sept 23, 1991, when the difference was about 10 hours, and it won’t happen again until the year 2029.
A Super Harvest Moon, a rare twilight glow, a midnight conjunction—rarely does autumn begin with such celestial fanfare.
Enjoy the show!
Watch out for the Super Harvest Moon – NASA Science
The Sky This Week, 2010 September 21 – 28 — Naval Oceanography Portal
This year’s Harvest Moon takes place within hours of the autumnal equinox, which falls on the 22nd at 11:09 pm EDT. At that instant the center of the Sun’s disc will be located directly over the Equator just west of Papua New Guinea, passing from the northern hemisphere of the sky into the southern hemisphere. Since the Sun subtends a tangible disc, though, the actual time when we see exactly 12 hours between sunrise and sunset won’t occur until a few days after the equinox. Here in Washington that phenomenon occurs on the 26th. This is also the time of year when the change in length of daylight occurs at its most rapid rate. There is no mistaking that the days are getting shorter!
The Sky This Week, 2010 September 21 – 28 — Naval Oceanography Portal