How to safely view a solar eclipse
Solar eclipses are safe to view with the naked eye during ‘totality’ (when the sun is completely blacked out) but aside from 100 per cent coverage, looking directly at the sun, even when when it’s 99 per cent covered is possibly harmful to the eye.
To avoid damaging your retina here are a few ways to view a solar eclipse.
Solar eclipse viewing: eyepiece projection
The safest way to see the eclipse is to use projection, by creating a pinhole or small opening in a piece of paper or plastic, which you attach to a tripod and adjust (without looking into it) the focus to cast the image of the Sun on to a screen.
“It takes a little practice, but if you can place a sheet of card behind the eyepiece, and shade it from the direct light of the Sun, you will find that a magnified image will be formed there,” says astronomer-in-charge at the Australian Astronomical Observatory and Australian Geographic columnist, Fred Watson. “A bit of judicious focusing will allow it to be sharpened up enough to see the Sun clearly.”
NASA suggests you can even create a basic projection by interlacing your fingers and letting the light fall through them onto another surface or the ground. You may even spot projections created naturally – such as the crescent shapes sometimes created by dappled light filtered through the leaves and branches of a tree.
Binoculars can also be used to magnify an image of the Sun onto a white card. Again, avoid looking at the Sun directly when you’re adjusting the light.
Solar eclipse viewing: eye guards
Eye guards that have filters with a thin layer of aluminium, chromium or silver adhered to their surfaces to weed out ultraviolet, visible, and infrared light can help you view a solar eclipse directly.
Number 14 welder’s glasses, available through welding supply outlets, are a relatively easily accessed means of protecting your eyes.
Some people also sheets of use aluminised mylar to create glasses or windows in boxes through which to view an eclipse.
Solar eclipse viewing: camera filters
Specialised camera filters can be used to photograph the eclipse, but they must be made for this purpose. Be warned: regular polarisers and filters won’t protect your eyes.