Harvest Moon and autumn equinox
Here within the Northern Hemisphere, we name the full moon closest to the autumn equinox the Harvest Moon. In 2021, the Northern Hemisphere autumn equinox comes on September 22. The full moon falls lower than two days earlier, on September 20. Thus, for the Northern Hemisphere, this upcoming full moon – the full moon closest to our autumn equinox – is our Harvest Moon.
Depending on the yr, the complete Harvest Moon can happen wherever from two weeks earlier than the autumn equinox to 2 weeks after. The Harvest Moon is both the final full moon of the summer time season, or the primary full moon in autumn. This yr, the September full moon is the fourth of the season’s 4 full moons. That’s the fourth moon of summer time for the Northern Hemisphere, and the fourth winter full moon for the Southern Hemisphere.
For the Southern Hemisphere, the Harvest Moon at all times is available in March or early April. It final passed off on March 28, 2021, and can subsequent occur March 18, 2022.
Most usually, a season has three full moons. This time round, nonetheless, 4 full moons happen in a single season: between the June solstice and September equinox. Four full moons in a single season is kind of atypical. Therefore, some folks consult with the third of those 4 full moons as a seasonal Blue Moon.
Actually, that definition of Blue Moon preceded the higher recognized definition. By popular acclaim, most regard a Blue Moon because the second of two full moons in a single calendar month.
What is the Harvest moon?
Harvest Moon is only a identify. In some methods, it’s like some other full moon name. But these autumn full moons do have particular traits associated to the time of moonrise. Nature is especially cooperative in giving us dusk-till-dawn moonlight, for a number of evenings in a row, across the time of the Harvest Moon.
On common, the full moon rises round sundown, and rises about 50 minutes later every day. But when a full moon occurs near an autumn equinox, the moon on the next nights rises nearer to the time of sundown. For mid-temperate latitudes, it rises solely about 20 to 25 minutes later day by day for a number of days earlier than and after the complete Harvest Moon.
For very excessive northern latitudes, there’s even much less time between successive moonrises. The farther north you reside, the larger the Harvest Moon impact. For occasion, at Anchorage, Alaska (61 degrees north latitude) the moon will rise at almost the identical time for per week!
The distinction between 50 minutes and 25 minutes may not look like a lot. But it signifies that, within the nights after a full Harvest Moon, you’ll see the moon ascending within the east comparatively quickly after sundown. The moon will rise throughout or close to twilight on these nights, presenting dusk-till-dawn moonlight for a number of nights in a row across the time of the Harvest Moon.
Why does this occur? Check out the illustrations under:
Is the Harvest Moon greater, or brighter or extra colourful?
Because the moon’s orbit round Earth isn’t an ideal circle, the Harvest Moon’s distance from Earth – and obvious measurement in our sky – differs from yr to yr. Last yr, in 2020, the Harvest Moon was the second-smallest full moon of 2020. In 2019, the Harvest Moon was truly a micro-moon or mini-moon: essentially the most distant and smallest full moon of the yr 2019. But 5 years in the past – September 28, 2015 – the Harvest Moon was the yr’s closest and largest supermoon.
No, the complete Harvest Moon will not be essentially nearer than some other full moon. It all will depend on the yr. In 2021, it’s just about an average-sized full moon.
Still, in any yr, you would possibly suppose the Harvest Moon appears greater or brighter or extra orange. That’s as a result of the Harvest Moon has such a robust mystique. Many folks search for it shortly after sundown across the time of full moon. After sundown across the time of any full moon, the moon will at all times be close to the horizon. It’ll have simply risen. It’s the placement of the moon close to the horizon that causes the Harvest Moon – or any full moon – to look big and orange in shade.
Orange shade resulting from thickness of Earth’s ambiance close to horizon
The orange shade of a moon close to the horizon is a real bodily impact. It stems from the truth that – while you look towards the horizon – you’re trying by means of a larger thickness of Earth’s ambiance than while you gaze up and overhead.
The bigger-than-usual measurement of a moon seen close to the horizon is one thing else fully. It’s a trick that your eyes are taking part in – an phantasm – referred to as the Moon Illusion. You can discover many prolonged explanations of the Moon Illusion by doing a web based seek for these phrases.
When is the Harvest Moon in 2021?
The actual time of the complete Harvest Moon is September 20 at 23:54 Universal Time. At U.S. time zones, that interprets to eight:54 p.m. ADT, 7:54 p.m. EDT, 6:54 p.m. CDT, 5:54 p.m. MDT, 4:54 p.m. PDT, 3:54 p.m Alaskan Time and 1:54 p.m. Hawaiian Time.
So look ahead to the Harvest Moon in late September and early October … or any of the nights round then.
By the way in which, as a rule, the September full moon is the Northern Hemisphere’s Harvest Moon. But if the full moon happens in early October – because it did in 2020 – the October full moon is that yr’s Harvest Moon.
How did the Harvest Moon get its identify?
The shorter-than-usual lag time between moonrises across the full Harvest Moon means no lengthy interval of darkness between sundown and moonrise for days in succession.
In the times earlier than tractor lights, the lamp of the Harvest Moon helped farmers collect their crops regardless of the diminishing daytime. As the sun’s mild light within the west, the moon would quickly rise within the east to light up the fields all through the night time.
Who named the Harvest Moon? That identify in all probability sprang to the lips of farmers all through the Northern Hemisphere, on autumn evenings, because the Harvest Moon aided in bringing within the crops.
The identify was popularized within the early twentieth century by the track under.
Shine On Harvest Moon
By Nora Bayes and Jack Norworth (1903)
Shine on, shine on harvest moon
Up within the sky,
I ain’t had no lovin’
Since January, February, June or July
Snow time ain’t no time to remain
Outdoors and spoon,
So shine on, shine on harvest moon,
For me and my gal.
And don’t miss this newer model of the track by Leon Redbone.
Bottom line: According to skylore, the closest full moon to the autumn equinox is the Harvest Moon. In 2021, the autumnal equinox for the Northern Hemisphere comes on September 22. So this hemisphere’s Harvest Moon comes on September 20.