A Moon for Harvesting Corn

A harvest Moon!
And on the mats-
Shadows of pine boughs.
–Takarai Kikaku, Japanese poet (1661-1707)

The Full Corn Moon corresponds with the time of harvesting corn. It is also called the Barley Moon because it is the time to harvest and thresh the ripened barley.

This month, we also celebrate what we call a Harvest Moon, which is the full Moon nearest the autumnal equinox. It can occur in September or October and is bright enough to allow finishing all the harvest chores. (This year it is September 29th.)  Many of us have heard about the “Harvest Moon” – it is even the stuff of songs.

The Moon rises about 50 minutes later because the Moon’s orbital motion (combined with the larger orbit of the Earth around the Sun) carries it farther eastward among the constellations of the zodiac from night-to-night. It takes an average of 50 minutes longer for the Earth to rotate toward the Moon and for the Moon thus to “rise.”

But around the date of the Harvest Moon, the Moon rises at almost the same time for a number of nights in our intermediate northern latitudes.

At one time, this full moon occurred when the peak of harvest time was a more important time in the lives of many Americans. It was a time that gave some extra light for farmworkers who had no artificial lighting to lengthen the picking day.  Harvesting today and crop harvest times have changed, so the “Harvest Moon” is more of a tradition than a reality.

The Harvest Moon was the only full moon given the same name by both the English, the Colonists 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.

The Harvest Moon is often depicted as a larger and orange-tinged moon. In reality, 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.)

As far as being a bigger moon, most adults know that the Moon’s size does not change and it’s not approaching closer to the Earth, despite the fact that it looks bigger at a different time and in different months. 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. This month’s low-hanging moon appears bigger and because of its position may also appear redder.

The full moons of September, October and November, as seen from the northern hemisphere, corresponding to the full moons of March, April and May as seen from the southern hemisphere.