Solar eclipse 2021: How and when to see in the UK
Time to break open your Sun safety glasses: this week, skygazers across the UK will be able to witness the biggest partial solar eclipse since 2015.
Although you won’t be thrown into complete darkness à la the eclipse of 1999, some areas of the nation will see nearly a third of the Sun’s light blocked by the Moon.
But exactly what time can you see the solar eclipse 2021 in the UK? Why does it happen in the first place? And is it really bad to look straight at the eclipse? (hint: if you’re not keen on frying your retinas, absolutely).
With the help of Dr Darren Baskill, physics and astronomy lecturer at the University of Sussex, all these questions and more have been answered below.
And if you’re interested in seeing more celestial spectacles, be sure to check out our full Moon UK calendar and astronomy for beginners guide.
What time is the solar eclipse in the UK?
The partial solar eclipse 2021 will start at 10:07am BST on Thursday 10 June in the UK.
It will reach its maximum at 11:14am, concluding at 12:26pm.
The times above are correct for the centre of the UK and will vary slightly with location.
Why does a solar eclipse happen?
Solar eclipses happen when the Moon comes between Earth and the Sun, the three celestial objects aligned so that the Moon leaves a shadow on Earth.
The type of solar eclipse that occurs depends on where the Moon is in its elliptical orbit (remember, it doesn’t travel around Earth in a perfect circle). If the Moon is at its closest point to Earth (called perigee) it can block out most of the Sun’s rays, creating a total eclipse.
However, if the Moon is aligned with the Sun when it’s near to its furthest point (called apogee) from the Earth, it won’t block out all light. Instead, it leaves a red ring or ‘annulus’ (Latin for ‘ring’) visible, creating what’s known as an annular eclipse.
“You always need to be in a very specific location to see an annular or total solar eclipse,” says Baskill.
“When the Moon moves in front of the Sun, it casts a shadow. That shadow is only a few hundred kilometres across – normally about 250 kilometres.
“And you need to be in that shadow to see a total solar eclipse. True, this shadow moves across different places as the Earth rotates. But, overall, it still covers a very small area.
“On Thursday, the Moon’s shadow will mainly fall across the Arctic and Greenland. But the Moon won’t be very close to the Earth, and so will not appear big enough to block out the Sun completely in those areas.
“This means that if you stood in those areas and looked up, they’ll be a small ring of red around the Moon’s shadow, what’s called an annular eclipse.”
Although those in the UK won’t be able to see an annular eclipse, they will be able to witness a partial eclipse. This is because the UK won’t be exactly aligned with the Moon and the Sun. The country will instead be covered by the Moon’s ‘outer shadow’ or penumbra.
Why isn’t there a solar eclipse every month?
There is not a solar eclipse every month as the Moon doesn’t orbit Earth in the same plane as Earth orbits the Sun. If it did, we’d have a solar eclipse every lunar cycle. Instead, the Moon’s orbit is tilted, its path only coming between Earth and the Sun during a period called eclipse season, which happens usually twice a year and lasts about 34.5 days.
As Baskill explains: “The Moon’s orbit is titled about five degrees. This means when it passes between the Earth and the Sun, the Moon is either below or above Earth.”
What will the 2021 solar eclipse look like in the UK?
The eclipse will look different in different parts of the world. Only people in Greenland, northern Canada and northeastern Russia will see an annular eclipse, with up to 89 per cent of the Sun obscured. In certain areas, a ‘ring of fire’ will be visible for over three minutes.
In the UK, people will see part of the Sun eclipsed by the Moon. The further north you are, the more you’ll see, with the north of Scotland witnessing over 30 per cent of the Sun eclipsed, compared to only 20 per cent in London.
Those in west Wales will see up to a quarter of the Sun eclipsed.
Is it dangerous to look directly at the solar eclipse?
Yes, it is always dangerous to look directly into the Sun. Doing so allows ultraviolet light to flood your retinas, which can permanently damage your vision.
“Just think of a really nasty child with a magnifying glass who likes to burn ants using the Sun. Then remember that you have a lens in each eye. And that if you look at the Sun, you’re burning your retinas in a similar way,” says Baskill.
“It’s particulary important not to look directly at this eclipse in the UK, with it happening in the late morning. At this time the Sun is high in the sky – with less atmosphere it is brighter and could do more damage.”
So, how can you safely look at the eclipse? Grab a colander and go outside. Simply hold it out and gaze down at the holes on the floor (place down a piece of white paper to help you see), each of which will show the crescent of the partial eclipse.
To clarify, you need to look at the ground at the gaps in the colander’s shadow – don’t place a colander on your head and stare upwards (not even you could pull off that look).
You can also use solar eclipse glasses that will sufficiently dim the Sun.
About our expert, Dr Darren Baskill
Dr 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 initiated the annual Astronomy Photographer of the Year competition.
Read more about the science of the Sun:
from... sciencefocus.com
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