As Portugal prepares for its first total solar eclipse since 1912 on Wednesday, August 12, 2026, high demand has completely exhausted free certified eclipse glasses within days. Experts and safety advocates are urging the public to avoid direct viewing without proper protection, turning instead to indirect projection methods using household items like shoeboxes and binoculars.
The upcoming celestial event has triggered a massive wave of public interest across the country, alongside immediate logistical shortages. In Leiria, free certified glasses distributed through a campaign by the Clube da Visão in partnership with Zeiss Vision Portugal vanished from optical shops almost instantly. Optometrist Tiago Jesus confirmed that they sold out right away and within two days, detailing how residents had to reserve the protective eyewear online before picking them up with a code at participating stores.
For those unable to secure the free certified supplies, alternative retail options remain available in pharmacies, select supermarkets, and online stores for roughly three euros. However, with demand outstripping supply, many residents are looking at clever do-it-yourself alternatives to safely witness the phenomenon without risking their eyesight.
Building a Safe Pinhole Projector and Camera Obscura at Home
Astronomers and science communicators emphasize that looking directly at the sun without certified filters can cause severe, lasting retinal damage, often without any immediate pain to signal the injury. To bypass the risk entirely, experts recommend indirect viewing techniques that require nothing more than basic household supplies.
Pedro Ré, president of the Portuguese Association of Amateur Astronomers, outlined several accessible methods in statements reported by TSF. One straightforward approach involves a simple piece of cardstock with a small perforation, projecting the sun’s image onto a secondary surface or the ground. Alternatively, a shoebox can be converted into a functional camera obscura.
Pedro Ré, president of the Portuguese Association of Amateur Astronomers, explained via TSF that they guide the sun’s direction using the shadow it casts on the ground, allowing people to peer inside the box and view the projected image, which is what is known as a camera obscura.
To construct the shoebox projector, a small pinhole is punched into one end, while a separate side viewing port is carved so the observer can look inward while standing completely with their back to the sun. The light enters the pinhole and casts an inverted, crescent-shaped projection onto the back interior wall of the box. Nature also provides its own pinholes; observers can photograph the ground beneath the canopy of a tree, where natural gaps project multiple miniature crescents onto the pavement.
For a more magnified setup, enthusiasts can rig a pair of binoculars to a tripod, shield the surrounding optics with a cardboard cutout, and project the focused solar image onto a blank sheet of paper detailed in instructions published by Popular Science. Experts strongly warn against looking through binoculars, telescopes, or standard sunglasses directly, as unverified lenses fail to block harmful radiation and can dangerously magnify light intensity.
The Rarity of the 2026 Eclipse and Where Visibility Peaks
The August 12, 2026 eclipse marks a historical milestone for the region. Portugal will witness its first total solar eclipse since 1912, though true totality remains restricted to a tiny pocket within the Montesinho Natural Park near Bragança, where the peak phase will last for just 26 seconds.
Across the rest of the Portuguese mainland, the event will appear as a partial eclipse, with solar occultation ranging between 92% and 99%. In the autonomous regions of the Azores and Madeira, visibility will drop slightly to between 74% and 77%. In Leiria specifically, the solar occultation will reach approximately 96%, beginning at 18:37, peaking at 19:34, and concluding at 20:27.
International visibility extends across a narrow corridor traversing the Arctic, Greenland, Iceland, and Spain, provided weather conditions allow for clear skies. Because the next total solar eclipse visible in Portugal will not occur until 2144, the 2026 event represents a rare viewing opportunity for multiple generations.
Protecting Vision and Finding Community Alternatives
Medical and optical professionals continue to sound warnings regarding the risks of solar retinopathy. Unfiltered exposure allows invisible radiation to pass straight through the eye’s natural lenses to the retina, potentially causing permanent vision loss that can take months to heal—with uncertain prospects for full recovery.
Any commercial eyewear purchased to view the sun directly must strictly comply with safety specifications, bearing the norm ISO 12312-2, the CE marking, and Regulation (UE) 2016/425. Standard sunglasses provide no protection against harmful non-UV radiation types.
Given the widespread shortages of certified glasses, municipalities, local associations, and scientific institutions are organizing public broadcast sessions and supervised indirect observation events. For those unable to secure personal gear, experts advise relying on these organized public gatherings or building a simple home projection box to experience the afternoon safely.
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