This September 18 to 19, the Harvest Moon will shine brightly in the night skies. There’s even an old standard written about this time of the year, and the Harvest Moon, called “Shine On, Harvest Moon.” But, exactly why is the full moon is September called the “Harvest Moon”?
The Harvest Moon is called that because it occurs around harvest time, and farmers, before the days of electricity, used to work into the night using the light of the full moon around harvest time to bring in their crops for the year.
According to NASA’s Dr. Tony Phillips on the Harvest Moon, the farmers used the light from it so that they could “gather their ripening crops in time for market. “
The Harvest Moon is sometimes referred to as Hunter’s Moon. The theory why is that Native Indians used the light from the full moon to hunt animals such as deer.
The time when the Harvest Moon appears in the night skies varies from year to year, anywhere from two weeks before to two weeks after the autumnal equinox.
When the moon is full and bright, as it is in the case of a “Harvest Moon,” you can see the large dark areas or maria (seas) of the moon without the use of binoculars.
The Harvest Moon is different from other full moons in that the difference in time between moonrises on subsequent evenings will be not as long as they would be with other moonrisess that occur during the rest of the year.
NASA Science News states that the moon rises, the rest of the year, “about 50 minutes later each day. But near the autumnal equinox..the day-to-day difference in the local time of moonrise is only 30 minutes.”
Though the Harvest Moon might seem bright, it isn’t a supermoon this year. The Last Harvest Moon that was also a supermoon was back in 2010. The next one will not be until 2029.
What sometimes makes the reddish orange color we see when the Harvest Moon rises or sets?
In some areas of the country, people might see a reddish orange glow when the Harvest Moon rises or sets, but the Harvest Moon isn’t colored any differently than any other moon, and people often see that color with any moon rise or set throughout the rest of the year.
The color comes from the reflected sunlight from the moon being scattered by the Earth’s atmosphere when the moon is nearer to the horizon. We see a red and orange glow because those two colors are not affected as much by the scattering, so that’s why the moon seems to have a reddish orange glow to it when it rises or sets.
Also, sometimes the Harvest Moon looks larger than other moons, but generally, that happens only every once in a few years, when the moon’s orbit might get a bit closer to the Earth. That will not happen this year.
If you happen to have the chance to get outside tonight, take a couple of minutes to take a look at the Harvest Moon, get some fresh air, and ponder the history behind why September’s full moon is called the Harvest Moon.
Written by: Douglas Cobb