How to watch the solar eclipse without hurting your eyes

Looking at the Sun, even briefly and even when it is almost covered, can burn the retina. It does not hurt and the damage can be permanent: it shows up hours later, as a spot in the middle of what you see.

In an annular eclipse you can never look at it without a filter, not even during the ring. The Moon covers about 86% of the Sun, but every point of what is left shines as bright as ever: the ring burns the retina just the same.

What works

Eclipse glasses with the ISO 12312-2 standard printed on them, from a reliable seller (planetariums, astronomy clubs, opticians). Before using them, check that they have no scratches or holes; if they are damaged, do not use them.
Put them on before looking toward the Sun and take them off only after turning away. If you wear glasses, they go over them.
Welder's glass number 14 (the number is engraved on it). A lower number is not enough.
Children, always with an adult next to them making sure they do not take them off.

What does not work (and is dangerous)

Sunglasses, even very dark ones or several pairs together.
X-ray film, photo negatives, glass smoked with a candle, CDs, cellophane or candy wrappers.
Binoculars, telescopes or a camera without a solar filter in front of the lens: they concentrate the light and burn the eye in an instant. Eclipse glasses do not work for looking through binoculars or a telescope: the concentrated light goes through them.

Watch it projected, without looking at the Sun

It is the safest way and you do not need to buy anything:

Make a small hole with a needle in the middle of a piece of cardboard.
Stand with your back to the Sun and hold the cardboard so the light passes through the hole.
Hold a white sheet of paper a meter away: you will see an image of the Sun almost a centimeter wide, with the Moon taking a bite out of it. The farther the sheet, the bigger the image (and the fainter).

A colander, a slotted spoon or your hands with the fingers crossed do the same with many holes at once. And under a tree, the gaps between the leaves project hundreds of eclipsed suns on the ground: at maximum, hundreds of rings.

Photos with your phone

Looking at the phone's screen is safe, but the unfiltered Sun can damage the sensor and the photo comes out burned: put a piece of solar filter (or the eclipse glasses) in front of the lens.

If you see a spot afterward

If after looking at the Sun you see a spot, everything blurry or strange colors, see an eye doctor.

Eclipse times in each city

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