Harvest moon

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For other uses, see Harvest Moon.

The Harvest Moon is the full moon nearest to the autumnal equinox, which occurs (in the northern hemisphere) on or about 23 September, and in the southern hemisphere on or about 21 March. Its physical characteristics - rising time, path across the sky - are similar to those of the Hunter's moon.

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. In general, the moon rises about 50 minutes later each day, as it moves in orbit around Earth. All full moons rise around the time of sunset. The Harvest Moon and Hunter's Moon are special because, around the time of these full moons, the time of moonrise on successive evenings is shorter than usual. In other words, the moon rises more like 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 of 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 bringing in their crops (or tracking their prey) by moonlight even when the sun had gone down. 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 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 2050 the Harvest Moon falls on October 7 in 1930, 1949, 1987, 2006 and 2025 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 a myth. 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.

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

A second full moon in a calendar month, or the third full moon in a season containing 4 full moons, is sometimes called a blue moon.

There is also a Harvest Moon Cocktail which is a mix of Guiness Ale and Blue Moon brew, invented at John Henry's Pub in Ardmore. Pennsylvania by R. S. Wenocur.

[edit] See Also

Mid-Autumn Festival

Similar behaviour to Harvest Moon has First Quarter Moon in December and Last Quarter Moon in June. This is because the narrowest angle of ecliptic falls on noon in December and on midnight in June and First Quarter Moon behaves like Full Moon 3 months earlier and Last Quarter Moon behaves like Full Moon 3 months later. There are 2 complementarily related reasons of minimum delay in moonrises: both the narrow angle of ecliptic and Moon's movement to north.

This isn't true, that the Harvest Moon goes along the sky at the low angle. It only seems when the Moon rises