

At any one moonrise, the Moon occupies a particular place on the celestial sphere (the great dome of the heavens), but when the Earth turns toward that point 24 hours later, the Moon has moved off to the east about 12 degrees, and it takes an average of 50 minutes longer for the Earth to rotate toward the Moon and for the Moon thus to “rise.” Think of it as a giant Slinky in which each loop, representing one lunar orbit of the Earth, advances the orbit a bit farther along the spiral path. 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. If interested, here is more detailed information about the Harvest Moon. (Warning: Scientific explanation below!) It may almost seem as if there are full Moons multiple nights in a row!

The Harvest Moon does typically occur in September, taking the place of the full Corn Moon. Instead, the Harvest Moon relates to the timing of the autumnal equinox(September 22, 2022), with the full Moon that occurs nearest to the equinox being the one to take on the name “Harvest Moon.” This means that the Harvest Moon can occur in either September or October, depending on how the lunar cycle lines up with the Gregorian calendar. One thing that sets the Harvest Moon apart from other full Moon names is that it’s not associated with a specific month, as the others are. EDT on Saturday, September 10 (it will be below the horizon at this time, however).

This year, the brilliant Harvest Moon first appears in the evening of Friday, September 9, before reaching peak illumination at 5:58 A.M.
