A bright Harvest Moon ushered in the changing seasons on Earth late Wednesday (Sept. 22) in a rare cosmic arrangement that has not occurred in nearly 20 years.
The full moon of September arrived on the same night as the autumnal equinox, which occurred last night at 11:09 p.m. EDT (0309 GMT Sept. 23) to mark the official start of the fall season in the Northern Hemisphere, as well as spring in the south.
Not since Sept. 23, 1991 has a full moon occurred on the same night as the fall equinox, and it won't happen again until 2029, wrote astronomer Tony Phillips in a NASA announcement.
According to Phillips, the Harvest Moon typically occurs a few days or weeks before or after the fall equinox. This year, though, the full moon occurs just six hours after the equinox, making it what Phillips called a "Super Harvest Moon."
Amateur astronomers around the world took advantage of clear skies to gaze at the bright full moon.
"Just so beautiful," wrote skywatcher Ruth Burkhead, who snapped a photo of the moon and Jupiter from her backyard in Eustis, Fla.
The September full moon also coincided with an alignment of Jupiter and Uranus, adding extra flavor to this year's fall equinox.
In K?nigswinter, Germany, skywatched Daniel Fischer said he couldn't let the moment pass without a photo.
"When the full moon, Jupiter in opposition and fall equinox all coincide, *something* has to be tried photographically," Fischer wrote on Twitter, where he posts sky photos under the name Cosmos4u. [Fischer's photo of the moon and Jupiter.]
An equinox is a time in which the sun is directly above Earth's equator, when the day and night are roughly the same length. There are two equinoxes each year, one in the fall and one in the spring.
Every full moon has a different name, one which varies depending on different cultures.
Harvest Moon gets its name from agriculture, Phillips
"In the days before electric lights, farmers depended on bright moonlight to extend the workday beyond sunset," Phillips wrote. "It was the only way they could gather their ripening crops in time for market."