A partial solar eclipse, which will be the most visible from the UK in 27 years, is set to take place on Wednesday evening. People are warned never to look directly at the sun and to use a pinhole projector or certified eclipse glasses instead. Check for the ISO standardWhen viewing the sun directly, you must use certified eclipse glasses that clearly state conformity to the ISO 12312-2 international safety standard. If you look through these devices while wearing your eclipse glasses, the magnified rays will instantly burn through the protective lenses and blind you. Provide one pair of eclipse glasses per person rather than passing a single pair back and forth, so protection is firmly in place before anyone faces the sun.