The Harvest Moon is the full Moon that occurs closest to the autumn equinox. Most years, that is September though it can be in October.  For 2011, the Full Moon is today, the 12th, and the equinox is just 11 days away on the 23rd.

At one time, this was not only the peak of harvest time but also a time that a full moon afforded some extra light so that workers could work into the night and pick by the light of this full moon.  Although harvesting today and even crop harvest times have changed a great deal, there is still something to the legend and tradition of a Harvest Moon.

It is still thought by many that the Harvest Moon is a kind of orange -tinged moon that is seen in autumn. Is there any truth to the idea that this Full Moon or lunar month is any bigger or brighter or more colorful than other moons?

These special effects have to do with the seasonal tilt of the earth. The warm color of the moon shortly after it rises is an optical illusion, based on the fact that when the moon is low in the sky, you are looking at it through a greater amount of atmospheric particles (including pollution) than when the moon is overhead. The atmosphere scatters the bluish component of but allows the reddish component of the light to travel a straighter path to your eyes. All celestial bodies look reddish when they are low in the sky. (Conversely, the idea that moonlight is blue (as it is often shown in art) is from the reflected white light from the sun.)

And is this Moon any bigger? Well, we know the Moon’s size does not change, and it’s not from it approaching closer to the Earth. The human eye perceives a low-hanging moon to be larger than one that’s high in the sky. This is known as a Moon Illusion and it can be seen with any full moon.  It is also true of constellations that are viewed low in the sky.

As we move through the seasons, the full Moon rises an average of 50 minutes later each night, but for the few nights around the Harvest Moon, the Moon seems to rise at nearly the same time each night – just 25 to 30 minutes later across the U.S., and only 10 to 20 minutes later for much of Canada and Europe.

The Harvest Moon was the only full moon given the same name by both the English and by many Native Americans of eastern and northern North America. Native American diet staples were corn, pumpkins, squash, beans, and wild rice, and all of them would typically be ready by this full moon (though, obviously, this varied by tribe and location). The Corn Moon was another Native American name for this September Moon. The Harvest Moon is also known as the Wine Moon, the Singing Moon, the Gypsy Moon, the Barley Moon and the Elk Call Moon.

Don’t confuse the Harvest moon with the Hunter’s Moon which is a more modern nickname for the Full Moon follows Harvest Moon. (That will be exactly one month from now on October 12.)

Did you know that the full moons of September, October and November as seen from the northern hemisphere correspond to the full moons of March, April and May as seen from the southern hemisphere?