Harvest moon

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This article is about the full moon nearest to the autumnal equinox. For other uses, see Harvest moon (disambiguation).

A Harvest Moon

The Harvest Moon is the first full moon after the first frost.

The Harvest moon is a legend in Norse mythology, it is said to be the most powerful of the Moons granting Loki's blessing for a strong harvest and plenty. The Harvest moon is often mistaken for the modern day Hunters moon.

In the legend of the Harvest moon it is said that all full moons have their own special characteristics based primarily on the whereabouts of the ecliptic in the sky at the time of year that these moons are visible. The full moons of September, October and November as seen from the northern hemisphere - which correspond to the full moons of March, April and May as seen from the southern hemisphere - are well known in the folklore of the sky. All full moons rise around the time of sunset. However, although in general the moon rises about 50 minutes later each day, as it moves in orbit around Earth, the Harvest Moon and Hunter's Moon are special, because around the time of these full moons, the time difference between moonrise on successive evenings is shorter than usual. In other words, the moon rises approximately 30 minutes later, from one night to the next, as seen from about 40 degrees N. or S. latitude, for several evenings around the full Hunter's or Harvest Moons. Thus there is no long period of darkness between sunset and moonrise around the time following these full moons. In times past this feature of these autumn moons was said to help farmers working to bring in their crops (or, in the case of the Hunter's Moon, hunters tracking their prey). They could continue being productive by moonlight even after the sun had set. Hence the name Harvest (or Hunter's) Moon.

The reason for the shorter-than-usual rising time between successive moonrises 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 is said to 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.

Norse mythology celebrates with gatherings, festivals, and rituals that are intricately attuned to the Harvest Moon or Hunter's Moon.

Often in the legend 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 orangish 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.

[edit] Other names

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

The third full moon in a season with four full moons is called a blue moon, as described in the Maine Farmer's Almanac. Until recently it was commonly misunderstood that the second full moon in a month was the blue moon. However, it was recently discovered by Sky & Telescope Magazine and reported on NPR that the interpretation of a blue moon as the second full moon of the month was erroneously reported in an issue of Sky & Telescope dating back to 1946 and then perpetuated by other media.

In some cultures, individuals whose birthdays fall on or near a harvest moon must provide a feast for the rest of the community.