What is the harvest moon, how to watch it? All to know about the supermoon

EXPLAINER

Appearing bigger than other supermoons, the harvest moon will rise on Thursday night, reaching its peak at 09:57 GMT.

Harvest moon, the last supermoon of the year – will rise on Thursday and reach its peak on Friday.

Although the harvest moon follows three supermoons already this year – the blue moon being the most recent – it is particularly unique.

Here is why:

What is the harvest moon?

The harvest moon is the closest full moon to the northern hemisphere’s autumn equinox which took place on September 23.

Along with marking the start of autumn, this equinox is a period when many crops reach their peak.

According to the Farmer’s Almanac, “this full moon rises at nearly the same time – around sunset- for several evenings in a row”. This results in an abundance of bright moonlight early in the evening.

Normally, the moon rises approximately 50 minutes later each day as it goes through its cycle. However, during the harvest moon, this delay is reduced to a smaller interval each night, according to the Farmer’s Almanac, ranging from 15 to 20 minutes in the northern United States and only 10 to 20 minutes later as you go farther north in Canada and Europe.

This supermoon has traditionally aided farmers and crews in harvesting their summer-grown crops by giving them several extra evenings of moonlight. Hence, it is called the harvest moon.

In China, a festival dating back to 771 BCE also celebrates the harvest of rice and white on the night of the full moon in autumn.

When will the moon appear, and how can you watch it?

This year, the harvest moon will appear just after sunset on Thursday, September 28, but it will peak at 5:57am ET (09:57 GMT) on Friday. A casual stargazer will still be able to see the full moon the night before and after its peak.

NASA also recommends using a pair of binoculars “with a magnification of 7 at a minimum. Though a magnification of 10 or 15 will provide more detail, you may need a tripod to steady them.”

At its highest point, the full moon will be at its closest point to the earth, experiencing a “lunar perigee”. And because it comes within 90 percent of the perigee, it is considered a supermoon.

The term “supermoon” was coined in 1979 by astrologer Richard Nolle to refer to the point when the full moon is at the closest point of its orbit around the Earth.

Why does the harvest moon look red?

The harvest moon has a shade of orange and red.

It appears bigger and brighter than other full moons because of an optical illusion that occurs when a moon is close to the horizon.

Its ochre-red colour is also more prominent when it is near the horizon. This is because the moonlight is filtered through more of the Earth’s atmospheric particles than when it is overhead.

The particles tend to scatter the blue light more than the red, allowing them to penetrate the eye.

Harvest moon festivals and folklore

Many cultures around the world celebrate the harvest moon.

Chinese and South Korean cultures are two of the biggest celebrants of the Harvest Moon Festival.

China has traditionally commemorated this mid-autumn festival, called Zhongqiu Jie, through family reunions, moon gazing and sharing mooncakes.

In South Korea, September 29 is a national holiday as a similar festival, Chuseok, is celebrated with people travelling to their ancestral and parental homes. During this celebration, they commemorate the autumn harvest. The festivity is also known as the Harvest Moon Festival.

According to ancient folklore, frost occurring in the light of the harvest moon would not kill fruit buds and blossoms, unlike frost in the dark of the moon.

Source

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Al Jazeera and news agencies