This Wednesday, millions of Britons will witness the best solar eclipse since 1999.
If you’ve still got a pair of eclipse glasses hanging around in the back of a drawer from the last eclipse, you might be tempted to use them.
However, experts have cautioned against this.
These decades–old pieces of safety equipment may have degraded since the last eclipse, meaning they don’t offer any real protection.
Scientists warn that using these worn–out eclipse viewers will put your eyes at risk of permanent damage and vision loss.
If you are planning on viewing the eclipse, experts recommend using specially made eclipse glasses bearing the ISO 12312–2 safety standard.
Dr Greg Brown, Astronomer at Royal Observatory Greenwich, told the Daily Mail: It is possible for the film on older solar eclipse glasses to degrade over time.
‘So it is recommended to only use eclipse glasses manufactured with the last decade.’
This Wednesday, millions of Britons will witness the best solar eclipse since 1999. But if you’ve been holding onto your glasses since then, experts say not to use them. Pictured: Spectators watch the 1999 eclipse at Edinburgh’s Royal Observatory on Blackford Hill
Although it might be tempting, experts stress that you must not look at the sun with your naked eyes at any point during the eclipse.
Mohamed Elalfy, a consultant ophthalmologist and president of the Royal College of Ophthalmologists, says: ‘Crucially, the retina has no pain receptors, so people will not feel the damage as it happens.
‘Symptoms may only become apparent several hours later and can include blurred vision, a central blind or dark spot, distorted vision, reduced colour perception and increased sensitivity to light. While some people recover over weeks or months, others can be left with permanent visual impairment.’
That makes it extremely important that you have the right protective equipment to view the eclipse, so that the bright light of the sun doesn’t cause serious damage.
Kyla Black, Boots Opticians Director of Optical Practice, says: ‘If you’re purchasing specially made eclipse glasses, make sure to double–check that they are undamaged before use as even a glimpse of damage could have an impact on your eyesight.’
That is especially important for older pairs which might have been scratched or scuffed while being stored over the last few decades.
You can check a pair for scratches by holding them up and looking at the brightest light in your house.
If the protection is still working, you shouldn’t be able to see even the slightest bit of light poking through.
Experts recommend using specially made eclipse glasses bearing the ISO 12312–2 safety standard. But glasses made before 2015 used materials that degrade over time, making them unsafe to use now
However, if the glasses are old or you aren’t quite sure, it is better to play it safe and get a new pair, which are cheaply available online or from institutions like the Royal Observatory Greenwich.
Likewise, using a pair of dark sunglasses isn’t enough to keep your eyes safe during the eclipse.
‘It’s a common myth that wearing multiple pairs of sunglasses can protect you from any harmful UV light,’ says Ms Black.
‘This is untrue and should be avoided at all costs as only purpose–built eclipse glasses can allow you to watch an eclipse.’
But if you don’t have a pair of eclipse glasses and can’t find one in time, there is still a way to enjoy the spectacle.
Dr Megan Argo, an astrophysicist from the University of Lancaster, told the Daily Mail: ‘The safest way for the public to enjoy the eclipse is to view it indirectly.
‘Standing beneath a leafy tree creates hundreds of tiny images of the Sun on the ground, which gradually change into crescents as the eclipse progresses.’
You can also replicate this process using a kitchen colander or a simple pinhole camera made from a cardboard box.
Outside of the UK, totality will be visible from Northern Spain, Greenland, Iceland, and parts of the Atlantic Ocean
‘Projecting the Sun safely with a colander, a pinhole viewer or by using a tree canopy, will help people see the shape of the Sun’s disk change as the Moon covers part of it for a couple of hours,’ says Dr Argo.
The eclipse will begin shortly after 18:00 BST on Wednesday, with the exact start time depending on your location.
Viewers will be able to see as the moon appears to take a ‘bite’ of the sun’s right–hand corner, before sliding over to cover almost the entire surface.
The deepest moment of the eclipse will come about an hour later, when parts of the UK will see up to 96 per cent of the sun vanish.
After shrinking to a slim inverted crescent, the sun will then begin to re–emerge, with the eclipse coming to an end shortly after 20:00 BST.
Unfortunately, the UK won’t quite get to see totality, but this will still be the biggest solar eclipse in over 26 years.
The very best place in the UK to see the eclipse will be Bishop Rock in the Isles of Scilly, where 96.5 per cent of the sun will be obscured.
That drops to just over 90 per cent for viewers up in Inverness, while London, Birmingham, Manchester and Edinburgh will all see roughly 91 per cent of the sun obscured.
