Harvest moon makes first October appearance since 2009

Oct. 5 (UPI) -- Thursday's evening sky will feature a "harvest" moon, the full moon closest to the autumnal equinox. This year, the equinox fell on Sept. 22.

Harvest moons often appear orange in the fading light of the sun, and signal the waning days of the harvesting season. This year's harvest moon marks the first time since 2009 the harvest moon has arced across an October sky.

While most harvest moons occur in September, an October harvest moon isn't necessarily rare.

"The previous one was in 2009, but the one before that was 2006, and the next one will be in 2020," Ernie Wright, scientist at the NASA Goddard Space Flight Center, told National Geographic.

By Wright's calculations, roughly one in four harvest moons rise in October.

Last year's harvest moon was a supermoon, as the moon was especially close to Earth.

In addition to appearing an orangish hue as it first rises, the harvest moon tends to bring a succession of brighter nights, as fuller moons rise almost immediately after the sun sets in the Northern Hemisphere.

In some Native American cultures, the harvest moon is referred to as the travel moon, dying grass moon or blood moon. The term harvest moon dates back to the early 18th century in Europe.

"People used to track the passage of time based on the moon," Andrea Jones, public engagement lead on NASA's Lunar Reconnaissance Orbiter mission, told Space.com. "The moon is a very obvious timekeeper for ancient civilizations."

The best views of Thursday's full moon will be in the West, South and Northeast. Views across much of the Midwest will be obscured by clouds.