How to Watch a Solar Eclipse Safely
Watching a solar eclipse is unforgettable — and completely safe, as long as you protect your eyes. The trouble is that the Sun stays dangerous to look at through almost every stage of an eclipse, and the damage it can do is permanent and often painless. Here is exactly how to watch without risking your sight.
Why the Sun is so dangerous
Looking directly at the Sun, even when it is mostly covered, can burn the light-sensitive retina at the back of the eye — a condition called solar retinopathy. There are no pain receptors there, so you will not feel the injury as it happens, and it can be permanent. That is why eye protection during an eclipse is never optional.
Use ISO 12312-2 eclipse glasses
The only safe way to watch the partial phases is through eclipse glasses or handheld solar viewers certified to the ISO 12312-2 standard, which block essentially all of the Sun's harmful light. Ordinary sunglasses — even very dark or polarised ones, and even several pairs stacked together — are thousands of times too bright and are never safe.
The one naked-eye moment
There is exactly one time it is safe to look with the unaided eye: during the totality of a total eclipse, when the Sun is one hundred percent covered, and only if you are inside the narrow path of totality. The instant the bright Sun starts to return — the 'diamond ring' — your glasses must go straight back on. An annular or partial eclipse never offers a safe naked-eye moment.
Cameras, phones and telescopes
Binoculars, telescopes and camera lenses concentrate sunlight and need a certified solar filter fitted over the front of the lens, never just over your eye. Looking at the Sun through unfiltered optics causes instant, serious injury. For a no-equipment option, use pinhole projection to cast the Sun's image onto a surface instead of looking at it.
Common questions
Can I watch a solar eclipse with sunglasses?
No. Ordinary sunglasses, even very dark or polarised ones, are thousands of times too bright to be safe. You need eclipse glasses certified to ISO 12312-2, or a projection method such as a pinhole.
When is it safe to look at an eclipse without glasses?
Only during the brief totality of a total eclipse, when the Sun is completely covered and you are inside the path of totality. At every other moment, and at every moment of a partial or annular eclipse, you need certified protection.
How do I know my eclipse glasses are safe?
Look for the ISO 12312-2 certification from a reputable maker, and check the filters for scratches, holes or damage. Through safe glasses the Sun appears as a sharp, comfortably dim disc and almost nothing else is visible.