How to watch the eclipse safely

The short version. Use certified eclipse glasses (ISO 12312-2) for every partial phase. Take them off only during totality itself, when the Sun is completely covered, and put them back on the moment any bright part of the Sun reappears. Looking at the Sun at any other time can burn your retina and cause permanent damage, often with no pain at the time.

Partial phases: always use certified viewers

Wear eclipse glasses or hold a handheld solar viewer that meets the ISO 12312-2 international standard for the whole of the partial phase, before and after totality.
Ordinary sunglasses are not safe, however dark they are.
Check your viewers before each use. Throw away any that are scratched, torn, punctured or coming away from the frame.
Supervise children so they keep their viewers on and do not look past them.
If you cannot see the Sun at all through the viewer, or your surroundings are visible through it, it is not dark enough.

Totality: the only time you can look with the naked eye

You can take your glasses off only during totality, when the Moon completely covers the bright disc of the Sun and you cannot see any part of it through your viewer. Totality lasts at most a few minutes, and shorter near the edges of the path (check the exact length for your spot on the map). As soon as any bright part of the Sun comes back, look away and put your glasses on. If you are outside the path of totality, there is no safe moment to look without protection: you only ever see a partial eclipse.

Cameras, binoculars and telescopes

Never look at the Sun through a camera, phone, binoculars or telescope while wearing eclipse glasses or holding a handheld viewer. The concentrated sunlight can burn through the filter and your eye.
Optical devices need their own solar filter, fitted to the front (the end that faces the Sun). Eclipse glasses are not a substitute.
If in doubt, ask an astronomy club or an astronomer before using a filter with any optical device.

Watch without looking at the Sun

A pinhole projector, such as a card with a small hole that casts an image of the Sun onto a surface behind it, lets you watch the partial phases with your back to the Sun. Look at the projection, never through the hole at the Sun.

Buying eclipse glasses

The American Astronomical Society keeps a free list of manufacturers whose viewers have been tested by accredited laboratories. Buy from a listed manufacturer or one of its authorised resellers.
You cannot tell a safe pair just by looking at it, and a safety claim or a listed company's name printed on the packaging is not proof. Be wary of pairs bought from an unknown seller through an online advert or search result.
A product should not claim to be "ISO certified": the standard is tested by laboratories, not by the ISO itself. Look for a maker's name and address, usage and warning instructions, and an ISO 12312-2 statement.

Sun protection

The Sun is strong during the long partial phases in the middle of the day. Bring water, a hat, sunscreen and shade, especially in the heat of an August afternoon.

Official guidance

This page is a summary. Read the original guidance, and re-check it before the eclipse.

We are not medical or optical experts. If you think you have looked at the Sun without protection and your vision is affected, see an eye doctor straight away.