Don't make Aug 21 a blind date: Beware crap solar eclipse specs

You'll be blinded by science, literally, if you put on fake glasses, boffins warn

The American Astronomical Society has warned that knockoff viewing glasses for this month's total solar eclipse will blind people if they wear them while looking up at the spectacle.

The total eclipse will plunge parts of America into darkness for a few moments on August 21, and appear as a partial eclipse in UK, Europe, and elsewhere. Before the Moon moves in front of the Sun, it's best to wear protection when looking up at the skies. It's also best to wear protection that actually works properly. Otherwise you'll be left seeing red, and then perhaps nothing at all.

Customs officers have been turning a blind eye to sub-par solar viewing equipment, it seems. The AAS says various companies selling the gear online are falsifying ISO safety stickers and reports, and thus the boffins are urging people to only use suppliers from the society's responsible vendor list.

"If we don't list a supplier, that doesn't mean their products are unsafe," says AAS task-force representative Rick Fienberg. "It just means that we have no knowledge of them or that we haven't convinced ourselves they're safe."

For those of you who have already bought your solar viewers, there are ways to check if they are safe. Just put them on and look at the lights in your house – if you can see the light bulb, the filters are too weak and you're risking eye damage.

A good filter will portray the Sun as a crisp pale image, not unlike the Moon. Useless viewers will show a haze around the Sun and make it appear out of focus. If you are going to test the devices using this method, make sure you only take a brief glimpse to avoid eye damage.

You might think that using industrial kit like welding goggles would be a safe way to watch this awesome event, but these can be just as dangerous. Welding goggles need to be using shades 12, 13, or 14 to be safe, which is much darker than most industries use. Shade 12 is probably too weak for the eclipse, though, shade 14 will be too dark, and shade 13 filters are hard to find.

The only time it's safe to look at the eclipse with the naked eye is when it's in totality, with the Moon entirely covering the face of our star. That will last a little over two minutes if you're directly under the path of totality.

If you do damage your eyes you'll be in good company. Isaac Newton and Galileo both wrecked their retinas by examining the Sun, but they didn't know any better at the time. You do – so goggle up and enjoy one of nature's most amazing natural phenomenons safely. ®

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