Harvest Moon begins on the nights of Sept. 29 and Sept. 30.
The Harvest Moon is the closest to the Autumn Equinox when full. The latest one occurs Oct. 11. It will be 100% full as it rises Sunday night.
Why is it called that?
It comes right at harvest time, and farmers had to work late into the night to get their crops in before the late-autumn freezes. But some sources note that there is a shorter period of darkness between sunset and moonrise this time of year in middle latitudes (because its orbit makes a narrower angle to the evening horizon around the equinox.) So that is an added boon for those hard-working harvesters.
The low angle also means that the moon’s light passes through more of the atmosphere and can seem redder and more colorful than ordinary full moons.
Many of the same factors (short gap between sunset and moonrise etc.) apply during the next full moon – the “Hunter’s Moon.” Since hunters also can benefit from some extra light at night. The Hunter’s Moon will be on Oct. 29.
If a Harvest comes on the same day as the equinox, it is called a “Super Harvest Moon.” The last one of these was in 2010 and the next one will be in 2029.
Something else happens this weekend with the planet Uranus, because it is now directly opposite of the sun in the sky. This means that the planet will rise as the sun sets, and set as the sun rises. It will be highest in the sky at local midnight, roughly 1 a.m. if you are on Daylight Saving Time.
Uranus was discovered accidentally by William Herschel on the night of March 13, 1781. All the other planets had been known since prehistoric times, so this was a major discovery in its time, and made Herschel famous.