A total solar eclipse is set to span North America on Monday – from Mexico to the very eastern tip of Canada.
The astronomical phenomenon will be less dramatic in the UK, but a partial eclipse could be visible in some parts of the country.
What is a solar eclipse and why is this one special?
A solar eclipse occurs when the Moon moves between the Earth and the Sun, blocking some or all of the Sun’s rays from reaching the Earth.
The phenomenon is a cosmic event, requiring the Sun, the Moon and the Earth to be in just the right alignment for the Moon to cast a shadow on our planet.
When this happens, the Moon casts two types of shadows.
One results in a partial solar eclipse, which covers only part of the Sun.
The other – and the more spectacular – is called a total solar eclipse, in which the Sun’s disc is entirely covered by the Moon, save for a delicate halo of scattered light coming from our star’s outer atmosphere.
A total solar eclipse occurs somewhere on Earth roughly every 18 months or so. The continental US was also lucky enough to see one in 2017, but its next significant opportunity won’t come until 2045.
How can I watch the total eclipse online?
It is due to start in Mexico shortly after 19:00 BST on Monday and the BBC website will have a livestream to watch the event as it happens and text and video updates on our live page.
It will continue throughout the day, complete with live dispatches from our reporters stationed at eclipse gatherings across the US and Canada.
What time is the solar eclipse in the UK, how long will it last and where can I see it?
It should be possible to catch a partial eclipse from western parts of the UK just before sunset – weather allowing.
Very simply, if you draw a line from about Fowey in Cornwall to Berwick upon Tweed in Northumberland, then everything west of that line might just get a view of the Moon biting the edge of the Sun as it disappears over the horizon.
You’ll need to be on high ground and have clear sky.
“With the partial solar eclipse occurring late in the day UK time, the Sun will be low to the horizon and will actually set before the spectacle is over,” BBC Weather presenter Simon King said.
The Moon’s full shadow ends its journey across the Earth in the Atlantic Ocean about 620 miles (1,000km) from Cornwall.
What will the UK weather be like for the eclipse?
The forecast for Monday evening isn’t ideal for the partial solar eclipse in the UK.
However, the best location for some clear skies, and conveniently where you’ll get the biggest eclipse, is the Western Isles of Scotland, according to Simon King.
“Generally, away from north-west Scotland it’ll be cloudy with rain at times providing a more disappointing weather-related eclipse of the Sun,” he said.
How can I safely watch the eclipse?
The old advice of never looking directly at the Sun still applies – you should not stare at the eclipse directly.
Experts recommend using solar eclipse glasses, which have a special filter that blocks damaging UV rays. These glasses are different from sunglasses, as they block all light entirely except that coming from the Sun.
If you can’t get glasses, try piercing a hole using a pin into one piece of paper. With your back to the Sun, hold that paper above your shoulder so the sun’s rays can shine through that small little hole.
At the same time, hold up another piece of paper in front of you.
It will act like a screen, on to which the Sun’s rays will be projected.
Where in the world will the total eclipse be visible?
People living in certain North American cities fall on the path of totality, which maps exactly where the total eclipse will be visible.
It spans locations from Mexico all the way to Newfoundland in the easternmost tip of Canada.
Big cities that should see the total eclipse include Dallas, Indianapolis, Cleveland and Buffalo, while Niagara Falls is expected to provide a spectacular view of the event.
For Canadians, the path of totality includes Hamilton, Montreal and Gander.
When was the last eclipse in the UK?
The UK’s last total solar eclipse occurred in 1999.
Thousands of people flocked to Cornwall, which was the only place in the UK to witness the event in its totality.
When is the next solar eclipse in the UK?
The next partial solar eclipse which will be visible from the UK is expected on 29 March 2025, when 30 to 40% of the Sun’s rays are expected to be blocked.
Then, on 12 August 2026, there will be an almost total eclipse, with about 90% of the Sun being obscured by the Moon.
However, the next full solar eclipse in the UK isn’t expected for another 66 years, on 23 September 2090, according to the Royal Observatory in Greenwich.
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