No matter where you live, the moon will look round and full tonight as it rises in the east around sunset. This is the full Harvest Moon for us in the northern hemisphere.
Every month has a full moon, and all the full moons have names.
The Harvest Moon is the name for the full moon closest to the September equinox, which came this year on September 23. This is the first full moon of autumn for us in this hemisphere. For the southern hemisphere, it’s the first full moon of spring.
Its known as the "Harvest Moon" because the moon once provided extra light for harvesting crops. The Harvest Moon is also known as the Wine Moon, the Singing Moon and the Elk Call Moon.
In myth and folklore the full moon of each month is given a name. There are many variations but the following list gives the most widely known names:
January - Wolf moon
February - Ice moon
March - Storm moon
April - Growing moon
May - Hare moon
June - Mead moon
July - Hay moon
August - Corn moon
September - Harvest moon
October - Hunter's moon
November - Snow moon
December - Winter moon
In some cultures, individuals whose birthdays fall on or near a harvest moon must provide a feast for the rest of the community.
To see the Harvest Moon, look to the east at sunset tonight.
The reason for the shorter-than-usual rising time between successive moon rises around the time of the Harvest and Hunter's Moon is that the ecliptic - or plane of Earth's orbit around the sun - makes a narrow angle with respect to the horizon in the evening in autumn.
The Harvest Moon can come before or after the autumnal equinox. It is simply the full moon closest to that equinox. About once every four years it occurs in October, depending on the cycles of the moon. Currently, the latest the Harvest Moon can occur is on October 8. Between 1900 and 2010 the Harvest Moon falls on October 7 in 1930, 1949, 1987, 2006, and on October 8 in 1911.
Many cultures celebrate with gatherings, festivals, and rituals that are intricately attuned to the Harvest Moon or Hunter's Moon.
It is claimed by some that the Harvest Moon seems to be somehow bigger or brighter or yellower in color than other full moons. This is an illusion. The yellow or golden or orange or reddish color of the moon shortly after it rises is a physical effect, which stems from the fact that, when you see the moon low in the sky, you are looking at it through a greater amount of atmosphere than when the moon is overhead. The atmosphere scatters the bluish component of white moonlight (which is really reflected sunlight) but allows the reddish component of the light to travel a straighter path to your eyes. Hence all moons (and stars and planets) look reddish when they are low in the sky.
As for the large size of a full moon when seen low in the sky, it is true that the human eye sees a low hanging moon as being larger than one that rides high in the sky. This is known as a Moon Illusion and can be seen with any full moon. It can also be seen with constellations; in other words, a constellation viewed low in the sky will appear bigger than when it is high in the sky.