Get ready, lunaphiles, tonight is not just any ol' Harvest Moon—it's a Super Harvest Moon. NASA says:

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.

In NYC, this will happen at 6:54 p.m.. NASA further explains, "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.'" The Super Harvest Moon hasn't happened since 1991 and won't happen again until 2029.

Then the autumnal equinox occurs at 11:09 p.m., when "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."

Asian cultures celebrate the autumnal equinox with the Mid-Autumn Festival (which includes yummy foods, of course). Of course, Mother Nature may be kicking over some storms—the National Weather Service has a severe thunderstorm watch until 11 p.m. for all of southeastern New York (except Suffolk County).