How Can You Safely Watch a Solar Eclipse?
A solar eclipse occurs when the Moon passes between Earth and the Sun. The Moon's shadow then falls across part of Earth, but what an observer sees depends on the shadow's position. During a total eclipse, the Moon completely covers the bright solar disk for a short period along a narrow path of totality. Outside that path, observers may see a partial eclipse, in which some of the Sun remains visible.
A photograph or social post can show that an eclipse occurred somewhere without confirming that it was visible from a particular city. The date, local start and end times, maximum coverage, weather, and path of totality should be checked with NASA, a national observatory, or a reputable local astronomy organization. Small differences in location can change the experience substantially.
Protecting your eyes
Looking directly at the uneclipsed or partially eclipsed Sun can injure the retina. Ordinary sunglasses, camera filters, smoked glass, and homemade viewers are not safe substitutes for equipment designed for solar observation. Use eclipse glasses or handheld viewers that meet the relevant ISO 12312-2 safety standard, and inspect them for scratches, holes, or other damage before use. Follow the manufacturer's instructions and do not use them with cameras, binoculars, or telescopes unless the optical equipment has a properly designed solar filter mounted over its front opening.
Children need close supervision because a brief unprotected glance can be harmful. People using prescription glasses can generally place a certified viewer over them if it fits securely, but should follow the product guidance. During totality only, observers inside the path may remove eye protection after the bright solar surface has completely disappeared. Protection must go back on before the Sun reappears.
Indirect viewing
A pinhole projector can display the Sun's shape on a nearby surface without directing the eye toward the Sun. A simple colander can create multiple small projected images, though the viewer should still avoid looking through the holes at the sky.
The safest plan combines certified equipment, an indirect method as a backup, and authoritative local timing information.