How to safely watch a solar eclipse without special glasses

As a solar eclipse approaches, many people look for ways to watch it without having bought special eclipse glasses in time. Fortunately, there are several simple techniques for viewing the event indirectly, without looking straight at the Sun.

Watching with a hand shadow

One of the easiest tricks requires no equipment at all: cross the fingers of both hands, leaving small gaps between them, then turn your back to the Sun and look at the shadow your hands cast on the ground. Each gap projects a tiny image of the Sun, which during an eclipse will appear as a small crescent of light. A similar effect can be achieved with a needle or a piece of cardboard with a small hole punched in it — in this case too, one should look at the projected image on a surface rather than through the hole directly at the Sun.

Why CDs and sunglasses aren't safe options

Although it's a popular online suggestion to view the Sun through a CD or DVD, this is not a certified solar filter and doesn't guarantee safe eye protection, so it shouldn't be relied upon. The same applies to ordinary sunglasses — even very dark lenses are not designed for direct solar viewing and don't provide sufficient protection for the eyes.

What actually is safe

For direct viewing of the Sun, special eclipse glasses or a filter meeting the international ISO 12312-2 standard are required, and it must be specifically designed for solar observation rather than simply dark material. If no such filter is available, the safest last-minute option is indirect projection — using hands, a needle, or a cardboard pinhole. If there's any doubt about the safety of a homemade solution, it's better to avoid looking directly at the Sun altogether, since eyesight is worth more than a single glimpse of an eclipse.