A glance at the Sun during an eclipse is one of the most impressive natural experiences. Without adequate protection it is dangerous: intense visible and invisible radiation can damage retinal tissue — often painlessly and permanently.
Why regular glasses are not enough
Sunglasses mainly reduce brightness, but do not sufficiently block ultraviolet and infrared radiation. Special solar-observation filters reduce visible light to a safe level and additionally block UV and infrared components. Only certified products provide the necessary protection.
Types of eclipse — and what they mean for safety
– Total solar eclipse: The Moon completely covers the solar disk. Only during the short period of totality may the Sun be observed without a filter. As soon as the Sun reappears as a crescent, protective filters must be put back on immediately. – Partial solar eclipse: Part of the Sun remains visible. Continuous eye protection is required throughout. – Annular solar eclipse: A bright ring of the Sun remains visible. At no time may it be observed without a filter.
Safe tools
– Solar eclipse glasses with ISO 12312-2: They reduce solar radiation to a safe level while protecting against UV and infrared components. – Full-aperture filters for optics: Binoculars, telescopes and cameras need solar filters mounted over the front of the objective designed for solar observation. Eyepiece filters are risky: the concentrated heat can destroy them. – Indirect methods: Projection methods are considered very safe — for example a pinhole projector (a hole in a card casts an image of the Sun onto a surface) or projecting the image through a telescope/binoculars onto a screen. Important: Never look through the device if no front filter is mounted.
Strictly forbidden
– Regular sunglasses, tinted films, CDs, X-ray films, scorched glass or improvised filters. – Looking through binoculars or a telescope without a suitable front filter: the concentrated radiation can damage eyes within seconds.
Viewing with children and in groups
Children often react spontaneously. Explain in advance how the glasses should fit and what to watch for. Group events should be supervised. Only lend glasses if they are undamaged and certified; do not use scratched or torn filters.
Photography and live streams
For photo and video recordings: always place a suitable solar filter in front of the lens — this protects the sensor and optics from overheating and glare. Never look through a camera with an optical viewfinder without a filter. As an alternative, consider reliable live broadcasts from official agencies and research institutions.
Symptoms — when to see a doctor
If, after brief observation, you notice blurred vision, spots in your visual field, altered color perception or other visual disturbances, you should consult an ophthalmologist immediately. Retinal damage does not always appear immediately but is often permanent.
Practical preparation
– Obtain certified glasses early — they sell out quickly before major events. – Check in advance that the glasses are undamaged: no scratches, cracks or loose parts. – Note local times for totality or maximum and be ready in time. – Plan a projection screen, spare batteries for camera/streaming and breaks in the shade.
Enjoy safely
With good preparation, the eclipse becomes a fascinating and safe experience: use protective glasses or an indirect viewing method, follow the rules for binoculars, telescopes and cameras strictly — and when in doubt, rely on verified live broadcasts.
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