The final supermoon of 2023 rises this week. What to know about the autumnal harvest moon.

The harvest supermoon − the last of four supermooons this year − will reach peak illumination at 5:57 a.m. EDT Friday.

The harvest moon is the full moon closest to the autumnal equinox, which this year was Sept. 23. It's called the harvest moon because it helped provide moonlight before electricity so farmers could harvest crops well into the night as autumn began.

The harvest moon has been an inspiration for musicians and artists, from Neil Young's song "Harvest Moon" in 1992 to George Inness' painting "Harvest Moon" in 1891.

This year's harvest moon will also be a supermoon.

What is a supermoon?

When the moon’s orbit brings it closer to Earth than usual, the cosmic combo is called a supermoon.

When this happens, the moon can appear slightly bigger and brighter than normal.

"Different publications use slightly different thresholds for deciding when a full moon is close enough to the Earth to qualify as a supermoon," NASA says. "Because the orbit of the moon is not a perfect circle, the moon is sometimes closer to the Earth than at other times during its orbit." 

On average, supermoons appear about 7% bigger and about 15% brighter than a typical full moon. 

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Moon calendar for the rest of 2023

A full moon typically occurs every 29 days, but because most months are 30 or 31 days, it is sometimes possible for two full moons to occur in the same month.

Contributing: Doyle Rice

SOURCE NASA; EarthSky.org; Old Farmer's Almanac; Paste BN research

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