How to Observe the Sun Safely

The only safe ways to observe the Sun are eclipse glasses or viewers certified to ISO 12312-2, a certified solar filter fitted securely over the front of a telescope, binoculars or camera, or projection methods like a pinhole card or a kitchen colander. Ordinary sunglasses, smoked glass and homemade filters are never safe, at any point during an eclipse, however dim the Sun looks.

That matters more than usual this year. On Wednesday 12 August 2026 the UK sees its deepest solar eclipse since 1999 — around 90% of the Sun covered from London and up to roughly 95–96% from Cornwall. First contact is around 6.17pm BST, maximum eclipse around 7.11pm, and it ends around 8.05pm, with the Sun low in the western sky throughout. Get your glasses or filter sorted now rather than on the night; our solar eclipse August 2026 UK guide has the full regional breakdown of times and coverage.

How Can You Look at the Sun Safely?

There are only three genuinely safe ways to observe the Sun: eclipse glasses or hand-held viewers certified to ISO 12312-2, a certified solar filter fitted securely over the front of a telescope, binoculars or camera lens, or projection — casting the Sun's image onto a card rather than looking at it directly. Everything else on the list below is a gamble with your eyesight, whatever anyone tells you.

Why Is Looking at the Sun Without Protection So Dangerous?

Looking at the Sun without proper protection causes permanent damage to the retina, known as solar retinopathy. The retina has no pain receptors, so the damage is completely painless — you won't feel anything while it happens, and you only discover it afterwards, when part of your vision doesn't come back to normal. Even a 96%-eclipsed Sun can injure your eyes in seconds; that thin remaining crescent is still intense sunlight.

This is why every recommendation on this page is deliberately strict. There's no "just a quick glance" that's safe, and there's no way to tell in the moment that harm is being done.

Never Look at the Sun Through a Telescope Without a Front-Mounted Filter

This is the single most dangerous mistake in solar observing, so it gets its own heading: never look at the Sun through a telescope, binoculars, a finder scope or a camera viewfinder unless a certified solar filter is fitted over the front (objective) end. Optics concentrate sunlight enough to burn through eclipse glasses instantly, so wearing your glasses while looking through an unfiltered eyepiece is not protection — it just adds a false sense of safety.

Cap or remove any finder scope before you start, since it's easy to forget it's still pointing at the Sun while you're focused on the main tube. If you've inherited a vintage telescope with a small screw-in "SUN" filter that fits onto the eyepiece, throw it away. Filters mounted there sit exactly where the heat and light are concentrated, with your eye a few centimetres behind, and they're known to crack under that heat.

Front-Mounted Filter Options

For the front end, two options work well. Certified solar film — the widely used Baader AstroSolar film is a popular choice — shows the Sun's white-light face clearly. Alternatively, a purpose-made glass or film filter sized to your telescope, binoculars or camera lens does the same job. Either way, it needs to fit snugly enough that a gust of wind can't dislodge it mid-session, and it's worth checking for pinholes before each session by holding it up to a normal light and looking for tiny points of light coming through.

How to Watch the Eclipse Without Glasses: Projection

If you don't have eclipse glasses, projection lets you watch the Sun safely without looking at it at all. Punch a small pinhole in a piece of card, hold it up so sunlight passes through, and let the image fall onto a second card held below — you'll see a small but clear image of the Sun's disc, crescent-shaped during a partial eclipse.

A kitchen colander does the same trick on a bigger scale: hold it up to the Sun and its dozens of holes throw dozens of tiny crescent suns onto the ground or a wall at once. Gaps between overlapping tree leaves create the same effect naturally, so keep an eye on dappled shade during the eclipse — you'll often spot crescent suns scattered across the pavement without doing anything at all.

For a bigger image, you can project through binoculars or a telescope onto a sheet of white card, but a few cautions apply. Never look through the instrument while you're aiming it — point it by watching its shadow shrink to its smallest, roundest shape instead. Never leave it unattended, especially around children, since anyone who does look through it risks the same eyepiece-concentrated damage described above. The heat can also damage eyepieces with cemented glass elements, and this method isn't suitable for Schmidt-Cassegrain or Maksutov telescopes at all, because heat builds up inside the closed tube.

Which Smart Telescopes Are Safe for Solar Viewing?

A smart telescope is currently the easiest safe route to seeing and photographing sunspots. The ZWO Seestar S50, Seestar S30 Pro and Dwarf 3 all come with a clip-on solar filter and a dedicated solar observing mode built into their apps. Fit the filter before you point the telescope anywhere near the Sun, not after — the app walks you through it, and the telescope tracks the Sun automatically once it's set up.

Can You Take Photos of the Sun With Your Phone?

For a zoomed-in shot of the Sun itself, your phone needs a solar filter over the lens, just like a telescope — the sensor can be damaged the same way your eyes can. The exception is a brief, wide-angle landscape shot during the eclipse: framing the horizon, the crowd or the changing light doesn't put the Sun large enough in the frame to need a filter. Just don't look directly at the Sun while you're lining the shot up. For everything else on getting good phone shots of the night sky, see our phone astrophotography guide.

What Will You Actually See When You Observe the Sun?

In ordinary white light, through a properly filtered telescope or binoculars, you'll see sunspots — dark blotches on the surface where the Sun's magnetic field is most active. We're near solar maximum, so the disc is usually busy with several visible at once. You'll also notice limb darkening, where the edge of the disc looks slightly dimmer than the centre, and during the eclipse itself, the sharp black edge of the Moon creeping steadily across the Sun's face.

For prominences and detail on the Sun's surface, dedicated H-alpha solar telescopes go a lot further, revealing flares and structure that are invisible in ordinary white light. They're a genuine step up in both capability and cost, and worth considering once you're hooked on solar observing rather than as a starting point.

Your Eclipse Day Checklist: 12 August 2026

Wednesday 12 August 2026 brings the UK's deepest solar eclipse since 1999, so it's worth planning the day properly rather than grabbing a pair of glasses on the way out the door. Work through these five things in order.

Frequently Asked Questions