Autumn equinox occurred at 4:44 pm ET last Sunday, September 22, officially marking the time of year we kick off the fall season in the northern hemisphere and the start of spring in the southern hemisphere. The word equinox comes from Latin refers to the 12 hour long equal day and night that occurs only twice a year.
The term "Harvest Moon" or "Corn Moon," is used to describe the full moon that occurs closest to fall's equinox. The annual celestial sight is referred to as the "Harvest Moon" because its light allowed farmers in the Northern Hemisphere to harvest their crops for several hours more into the night. For skywatchers in North America, the full moon is expected to rise shortly after sunset (depending on your location) on September 18 and will peak at 7:13 a.m. EDT the next morning.
No matter where you are on Earth, every full moon ascends over your eastern horizon around the time of sunset. It’s always highest in the sky in the middle of the night, when the sun is below your feet because a full moon is opposite the sun. Being opposite the sun, the moon is showing us its fully lighted hemisphere, or “day” side, making the moon appear full.However, the almost full Harvest Moon should also be visible for North American viewers on Thursday night, when the moon will turn full for observers in Asia.
Harvest moon seen the evening of Sept. 29, 2012 (Fox 11 News)
While the moon did light the sky enough to leave some faint shadows in the yard this year, the sky was a bit hazy so the harvest moon was not quite as bright in the sky as we've experienced during past full moons, when the moon shines in the window, waking us to observe light bright enough to leave discernible shadows in the yard below.