For the first time this century, people across the UK will be able to see an almost total solar eclipse in the evening sky on Wednesday.
A solar eclipse occurs when the moon moves between the sun and the Earth, blocking the sun’s light either partly or fully. This year, people in the UK and Ireland will see ۹۰-۹۶% of the sun covered by the moon for the first time since ۱۹۹۹ – and it’s their last chance until ۲۰۸۱.
Across north-western Europe, people will see about ۸۸-۹۵% coverage, while spectators in parts of Greenland, Iceland and northern Spain will see a total eclipse for up to two minutes and ۱۸ seconds in duration.
In the UK, viewers in the west will see the most of the sun obscured: ۹۵% in Plymouth, ۹۳.۲% in Cardiff and ۹۳.۱% in Belfast. Spectators in Manchester will see ۹۱.۹% and Londoners will catch ۹۱.۴%. Farther north and east people will see smaller proportions, with Edinburgh at ۹۰.۷%, Newcastle at ۹۰.۲%. Shetland will have the lowest coverage at ۸۸%.
Royal Observatory Greenwich astronomer Jess Lee said that these are small differences, and all “will still be impressive sights”. She recommended finding hills with clear views to the west, for example Parliament Hill, Alexandra Palace or Primrose Hill in London, or rooftop venues.
Because the eclipse takes place in August, there’s a stronger chance of clear skies. Tom Morgan, a Met Office meteorologist, said it was too early to be confident, but “given the summer we’ve had a lot of the UK will have reasonable viewing conditions”.
At present, there is a higher risk of thick cloud and rain in Scotland and Northern Ireland, while the clearest skies are likely to be towards the south and the east of the UK. “For many it’ll be quite a spectacular and rare event,” he said.
For Scotland’s astronomer royal, Catherine Heymans, keeping an eye on the clouds is the secret to scoring the best view, since these could partly or entirely obscure the eclipse.
“I plan to check the Met Office’s fantastic online cloud cover forecast as we get closer to the day. I’m ready to hop on a train north, south, east or west to find some cloud-free skies,” she said.
Getting to a high point with a clear view of the horizon also helps. “I’d recommend a dress rehearsal in the days before. If you can’t see the sun from your planned viewing spot at ۷.۳۰pm because your view is blocked by a hill or a house, then you’ll want to find yourself a different location for the real event,” Heymans added.
The most important thing, she stressed, is to wear eclipse glasses and avoid looking directly at the sun.
During an eclipse, the sun appears dimmer, making it easier to look at directly. However, solar radiation can still reach and damage the retina, often without causing any pain, so viewers may not realise harm is occurring until it’s too late.
Following the ۱۹۹۹ total solar eclipse, the Royal College of Ophthalmologists reported about ۷۰ cases of people experiencing vision problems after watching the eclipse.
The UK Health Security Agency advises that there are two safe approaches: specialist eclipse viewers or indirect viewing methods.
Eclipse glasses or handheld solar viewers must be genuine and sold by a reputable retailer, and should have specially designed filters that meet the international safety standard ISO ۱۲۳۱۲-۲:۲۰۱۵(E), and no scratches, tearing or damage to the lens. Old pairs may not be reusable and sunglasses should never be used.
Indirect view methods include viewing the sun’s image projected through a colander or the gaps between tree leaves on to white paper, or using a pinhole pierced in one sheet of card and projected on to another.
Sarah Crowther, an astronomer at the University of Manchester, said it was important to remember that the solar eclipse would take place at different times across the UK.
It starts at about ۶.۰۸pm in Edinburgh and Glasgow, ۶.۱۰pm in Belfast, ۶.۱۳pm in Manchester and Liverpool, ۶.۱۵pm in Birmingham, ۶.۱۷pm in London and ۶.۱۸pm in Cornwall. Maximum eclipse follows roughly an hour later, ending about ۸pm.
People might observe the surrounding area going quiet during the solar eclipse, “when animals think it is night because it is darker, which gives a sense of calm. And then there’s an awakening as it gets light again, birds think it is dawn so there could be a dawn chorus,” said Crowther.
She added: “I think many people feel a sense of awe when they see an eclipse. It can put the vast scales of the solar system into some kind of perspective.”
