October Full Moon 2019: Orange Full Hunter's Moon to Appear in Night Sky

This October, a Full Hunter's Moon will appear in the night sky.

Full moons occur roughly every once a month when the Earth is positioned directly between the sun and the moon. In these instances, it is fully illuminated, appearing like a perfect circle.

The October full moon will reach its peak on Sunday, October 13, at 5:08 p.m. EDT, although it will appear full to the naked eye for about a day on either side of this date, according to The Old Farmer's Almanac.

The full moon will rise around sunset. When it is near the horizon, it may appear larger and more orange than when it's positioned higher in the sky due to the so-called "moon illusion."

"When the moon is high overhead, it is dwarfed by the vast hemisphere of the heavens and appears to our eyes as a small disk in the sky," Bob Berman, an astronomer for the Farmer's Almanac, wrote.

"By contrast, when the moon is low, it is viewed in relation to earthly objects, such as chimneys or trees, whose size and shape provide scale," he said. "Your brain compares the size of the moon to the trees, buildings or other reference points, and suddenly, the moon looks massive!"

The reason that it appears more orange nearer the horizon is due to the effect of the Earth's atmosphere, according to Berman.

"The light that's being reflected off of a horizon-hugging moon has to travel through more particles of air to reach your eyes," he wrote.

"By the time we perceive this light, the shorter wavelengths of light, the 'blue' ones, have been scattered by the air, leaving only the longer wavelengths, the 'red' ones, to reach our eyes," he said. "Thus, to us, the bluish hues are filtered out, and the moon takes on an orange tinge!"

On the other hand, when the moon is directly overhead, the light does not have to travel through as many air particles to reach us, thus it is scattered less. This enables more of the blue wavelengths to reach our eyes, lending the moon a brighter, less orangey color.

Unlike most other full moon names, the term "Hunter's Moon" is not tied to a specific month. In fact, Hunter's Moon is the name given to whichever full moon comes after the Harvest Moon—or the one closest to the autumn equinox in the Northern Hemisphere.

As result, the term "Hunter's Moon" can be used for full moons that fall both in October and November, depending on the year. This year, the Harvest Moon occurred on Friday, September 13, for those living in the Eastern time zone.

The name of the Hunter's Moon is thought to come from Native American folklore. One explanation is that the period after the autumn harvest was a good time to go hunting in preparation for winter.

Full Hunter's Moon
One day after the Full Hunter's Moon, the moon rises behind lower Manhattan and One World Trade Center in New York City on October 25, 2018, as seen from Green Brook Township, New Jersey. Gary Hershorn/Getty Images
October Full Moon 2019: Orange Full Hunter's Moon to Appear in Night Sky | Tech & Science
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