The safest way to view a solar eclipse is with eclipse glasses that meet the ISO 12312-2 international safety standard, which block all but a tiny fraction of the sun’s light. If you don’t have certified glasses, a simple pinhole projector made from household materials lets you watch the eclipse indirectly. Both methods work well, but getting the details right matters: unprotected glances at the sun, even during a partial eclipse, can cause lasting damage to your vision in seconds.
Why Your Eyes Can’t Handle It
Staring at the sun during an eclipse concentrates light energy on the macula, the small area at the center of your retina responsible for sharp, detailed vision. This causes a condition called solar retinopathy, where photochemical and thermal damage destroys photoreceptor cells and the pigment layer behind them. The injury is painless while it’s happening because the retina has no pain receptors, so you won’t feel a warning signal telling you to look away.
Symptoms typically appear within hours: blurred central vision, blind spots, sensitivity to light, and distorted or wavy vision. Most people recover fully within a few weeks to six months. In a study of 70 solar retinopathy cases from a 1999 eclipse, all patients regained normal vision within six months. But recovery isn’t guaranteed. Some people are left with permanent blind spots in their central vision that interfere with reading, driving, and recognizing faces.
Choosing Safe Eclipse Glasses
Legitimate eclipse glasses comply with ISO 12312-2, which sets strict limits on how much ultraviolet, visible, and infrared light can pass through the lenses. When you put on a compliant pair, the only thing you should be able to see is the sun itself. If the lenses let you see ordinary lights, streetlamps, or your surroundings, they aren’t filtering enough.
The American Astronomical Society maintains a list of vetted manufacturers and sellers on their website. Before buying, check that the vendor appears on that list. Do not search Amazon, eBay, Temu, or other online marketplaces and grab the cheapest option. Counterfeit glasses that look identical to real ones have flooded those platforms before past eclipses. If you received glasses from a science museum, planetarium, university astronomy department, or astronomy club, they’re almost certainly safe. Astronomers source their filters from trusted suppliers.
Before using any pair, inspect the lenses for scratches, punctures, or peeling. If the filter material is damaged in any way, discard the glasses.
Using Binoculars, Telescopes, or Cameras
Regular eclipse glasses are not a substitute for a proper solar filter on optical equipment. Looking through binoculars or a telescope while wearing eclipse glasses is extremely dangerous. The optics concentrate sunlight so intensely that it will burn straight through the glasses and into your eye.
Any telescope, binoculars, or camera lens pointed at the sun needs a dedicated solar filter attached to the front of the instrument, covering the opening where light enters. Filters that screw into the eyepiece at the back end (where you look through) are unsafe. Concentrated sunlight inside the tube can shatter them instantly. If you own one, throw it away. Front-mounted filters come in three common types: metal-coated glass, aluminized polyester film, and black polymer. All work, though metal-coated glass tends to be the most durable.
Photographing the Eclipse With a Phone
You can photograph a partial eclipse with a smartphone, but you need a certified solar filter over the camera lens. Prolonged unfiltered exposure to sunlight can damage your phone’s sensor and optics, and you risk glancing at the sun while framing the shot. A sheet of ISO 12312-2 certified solar film (like Baader AstroSolar film, which blocks 99.999% of sunlight) can be cut to size and taped over the lens.
Once your filter is in place, reduce the exposure. On an iPhone, tap the screen and drag the exposure slider down, or swipe up and use the plus/minus control to lock a lower exposure for multiple shots. On Android, tap the image and adjust the slider, or switch to Pro mode for manual exposure compensation. Keep the solar filter on for the entire partial phase. The only time you’d remove it is during totality, if you’re viewing a total eclipse.
Building a Pinhole Projector
If you don’t have eclipse glasses, a pinhole projector is the easiest no-cost option. You never look at the sun at all. Instead, you project a small image of it onto a surface and watch the moon’s shadow cross that image in real time. Here’s how to build one in about two minutes:
- Gather materials: two pieces of white card stock, a small piece of aluminum foil, tape, and a pin or paperclip.
- Cut a window: Cut a one- to two-inch square hole in the center of one piece of card stock.
- Add the foil: Tape a piece of aluminum foil over that hole so it’s smooth and flat.
- Make the pinhole: Use the pin to poke a single small hole through the foil.
- Project the image: Stand with the sun behind you. Hold the foil card up and let sunlight pass through the pinhole onto the second piece of card stock below. A small, circular image of the sun will appear on the lower card.
The farther apart you hold the two cards, the larger the projected image. For a sharper picture, keep the bottom card in a shadowed area while holding the top card in direct sunlight. You can also use a colander, a straw hat, or even the gaps between interlocked fingers. Anything that creates small holes will project dozens of tiny eclipse images on the ground.
What Happens During Totality
If you’re within the path of a total solar eclipse, there’s a brief window, usually just a few minutes, when the moon completely covers the sun’s bright face. This is the one moment you can look directly at the eclipse without any protection. You’ll know it’s safe when you can no longer see any part of the sun through your eclipse glasses. At that point, take them off and look up.
Totality reveals the sun’s corona, a wispy, glowing halo of superheated gas that’s normally invisible. The sky darkens to twilight, stars and planets may appear, and the temperature drops noticeably. It’s the reason people travel thousands of miles for eclipses. But the window is short. The instant you see even a sliver of bright sunlight returning at the moon’s edge, put your glasses back on immediately. That first reappearing crescent is every bit as dangerous as the partial phases that preceded totality.
Annular eclipses, where the moon doesn’t fully cover the sun and a bright ring remains visible, are never safe to view without protection. The ring of sunlight is more than enough to cause retinal damage.
Upcoming Solar Eclipses
The next total solar eclipse occurs on August 12, 2026, with the path of totality crossing Greenland, Iceland, and Spain. A partial eclipse will be visible across most of Europe, parts of Africa, and portions of North America.
On February 6, 2027, an annular eclipse will cross parts of South America and West Africa, including Chile, Argentina, Ghana, and Nigeria. Then on August 2, 2027, a total eclipse will sweep across southern Spain, Morocco, Algeria, Tunisia, Libya, Egypt, Saudi Arabia, and Yemen. A partial eclipse from that event will be visible across most of Europe, much of Africa, the Middle East, and even northern Maine in the United States.
Planning ahead gives you time to order certified viewers, scout a viewing location, and avoid the last-minute scramble for glasses that tends to leave people stuck with counterfeit products or no protection at all.