How to see the Pink supermoon 2021 tonight
Find out when you can spot the fourth full Moon of this year – and why it will be the brightest of 2021 so far.
Missed last night’s Pink supermoon? Good news: the April full Moon, the fourth of 2021, will also be visible this evening. And, just like last night, it will appear a massive 30 per cent brighter and 14 per cent larger than some previous full Moons.
So, why exactly does the supermoon seem so large? What’s the best way to photograph it? And will it actually look even slightly pink? All answers to these lunar inquiries (and more) are below.
When is the Pink supermoon 2021?
The Pink supermoon can be seen from Monday 26 April 2021 in the UK (and around the rest of the Earth).
Astronomically speaking, the Moon is only ‘full’ – reflecting the maximum amount of sunlight onto Earth – for only a brief period of time. This happens when Earth comes exactly between the Moon and The Sun, a moment called ‘syzygy’.
In the UK, this will happen at 4:13am on 27 April. But don't worry about staying up late for this moment: to the naked eye, the Moon will appear full for another two to three nights afterwards.
Will the Pink supermoon actually be pink?
Bad news: the pink moon 2021 will not appear in the night sky with a red hue.
Well, not all night, anyway. Just like any full Moon, it could appear slightly pink as it passes across the horizon.
“The Moon will slightly change colour depending on where it appears in the sky,” says Dr Darren Baskill, physics and astronomy lecturer at the University of Sussex.
“It’s all to do with the curvature of Earth. When you stand outside at look directly up, you’re looking through about 30km of atmosphere. But look to the horizon and you’re looking through about 300km of atmosphere.
“As blue (shorter wavelength) light ‘bends’ or ‘scatters’ more than red light, not as much of it will reach your eye through 300km of atmosphere. So only the more red colours will reach you. This means the Moon (and the Sun) take on a reddish colour when they’re on the horizon.”
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Why is it called a pink moon?
As we explain above, the full Moon won’t appear pink all night. So where does it get that name? In short: not from science.
Many claim the April full Moon was named by a group of Native Americans after the pink moss (creeping phlox) that grows during this time of the year. However, the name 'Pink Moon' is by no means official.
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“No one seems to know who is inventing these generalisations,” says Baskill.
He adds: “People often say that we take our Moon names from the ‘Native Americans’, but they weren’t one group of people. There’s a danger of being culturally insensitive here. The USA is a massive landmass and was home to many different types of people.”
Indeed, over a thousand languages are spoken by Native Americans, and their cultures are as diverse as Europeans. As such, many different Native American groups have given the April full Moon different names, including the ‘Sugar Maker’ Moon, the ‘Moon of Blackberry’ and the ‘Egg Moon’.
What causes a supermoon?
The Moon doesn’t orbit Earth in a circle, thanks to being pulled around by various gravitational forces like the Earth and the Sun. Instead, it moves in an elliptical shape, and how close it gets to Earth varies month by month.
At a certain point in its orbit, called perigee, the Moon reaches its closest to Earth. Then at another point, apogee, it is furthest away. The difference between these two points is an average of 48,000km.
A supermoon occurs when we have a full Moon at the same time the Moon is at (or close to) perigee. This makes it appear up to 14 per cent bigger and 30 per cent brighter than a full Moon at apogee (when it’s furthest away and looks smaller and dimmer).
One in every 14 full Moons will be a supermoon, on average, but they sometimes come two in a row because of the cycle of the Moon’s orbit and its phases briefly syncing together. – by Abigail Beall
How far away from Earth is a supermoon?
Astronomically, there’s no official definition of a Supermoon. Some, such as astrologer Richard Nolle (who coined the term in 1979) claim that any Moon that comes closer than 368,630km to the Earth as it appears ‘full’ can count as a ‘Supermoon’.
(The average distance between Earth and the Moon is about 382,900km, with 2021's full Pink Moon being about 357,615 km away from us).
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However, many astronomers categorise a supermoon as a Moon that appears full while positioned at least 90 per cent to its closest approach to Earth. Using this definition, there are two supermoons in 2021: on 27 April and 26 May.
Although you won’t be able to tell the difference with the naked eye, the May supermoon will actually be slightly larger, being an extra 157km closer to Earth.
Do supermoons cause natural disasters?
No. There are no proven links between supermoons and natural disasters such as tidal waves. But we understand why you asked.
“It’s true that about two-thirds of tides are influenced by the gravity of the Moon (and a third the Sun). We get high tides when the Sun and Moon are aligned – at a full or new Moon,” explains Baskill.
“As the Supermoon will be closer to Earth than a normal full Moon, it will have a greater tidal force – but this will only change the tide by a few centimetres.”
How often are full Moons?
A full Moon happens roughly every 29.5 days (the length of one lunar cycle).
This means it occurs around once a month – interestingly, the English word for ‘month’ is actually rooted in the word ‘Moon’.
The next full Moon, which some call the ‘Flower Moon’, will occur on Tuesday 26 May 2021 and (lucky you) will also be a supermoon.
What’s the best way of photographing the Pink supermoon?
With the Moon big and bright this month, it will be easier to photograph than normal. However, there are still some major pitfalls to avoid.
The first: the flash. Turn it off. It will do nothing to illuminate the night sky and will only result in a worse photo.
If you’re trying to snap the Moon with your phone, it’s also a good idea to lower your camera’s ISO sensitivity and raise your focus to 100. To make this easier, you can download one of the many astronomy photography apps. NightCap – available on the App Store, £2.99 – is our top pick, making it onto our list of best astronomy apps.
If you’ve got a professional camera, select your lens wisely. “You need a reasonable zoom lens to capture a detailed picture,” explains Baskill.
He also recommends an aperture of f/9 to f/10 to achieve a sharper image, with a shutter speed of between 1/60th and 1/125th of a second.
Warning: with this slow shutter speed, you may be best using a tripod. “It’s better, but you don’t need one,” says Baskill. “I find propping the camera up on the garden fence keeps it steady enough for some great photos!”
About our expert, Dr Darren BaskillDr Baskill is an outreach officer and lecturer in the department of physics and astronomy at the University of Sussex. He previously lectured at the Royal Observatory Greenwich, where he also created the annual Astronomy Photographer of the Year competition.
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Thomas is a Staff Writer at BBC Science Focus and looks after all things Q&A. Writing about everything from cosmology to anthropology, he specialises in the latest psychology and neuroscience discoveries. Thomas has a Masters degree (distinction) in Magazine Journalism from the University of Sheffield and has written for Men’s Health, Vice and Radio Times. He has been shortlisted as the New Digital Talent of the Year at the national magazine Professional Publishers Association (PPA) awards.