On 12 August 2026, Spain will witness its first total solar eclipse visible from the mainland in over a century. It is the first of a Trio of Eclipses that will continue in 2027 and 2028, an event significant enough for the Spanish Government to launch a dedicated official website: trioeclipses.es
We already covered how to protect your eyes and watch the eclipse safely. This year, we have our own eclipse glasses available, with a Zeiss-certified filter, for €4.50.
What glasses do you need to watch a solar eclipse?
To watch a solar eclipse safely, you need glasses fitted with a certified filter that complies with ISO 12312-2:2015. This standard reduces visible light to levels safe for the retina and blocks 100% of ultraviolet radiation. Standard sunglasses, however dark, do not meet this requirement.
Most eclipse guides will tell you the same things: don’t look directly at the Sun, use certified glasses, check for the CE marking. All true,but they skip the more important question: what is actually behind that filter?
Why the filter matters more than the frame
An eclipse filter is not a tinted lens. It is a precision optical component designed to do one specific thing: reduce visible light transmittance to a maximum of 0.00032% ( optical density 5.5 ) while blocking 100% of ultraviolet radiation and at least 97% of infrared.
For comparison: standard sunglasses, regardless of how dark they appear, transmit between 8% and 18% of light. The difference between sunglasses and an eclipse filter is several thousand times over.
That level of precision , calculating to the thousandth how much light should pass through a lens, and ensuring it does so uniformly across the entire surface, is exactly the territory where Zeiss has been building its reputation since 1846.
Zeiss: nearly two centuries calculating light
Carl Zeiss opened his first optical workshop in Jena in 1846. For the first two decades, manufacturing quality optical instruments relied largely on trial and error. That changed in 1866 with the arrival of physicist Ernst Abbe, who replaced intuitive craftsmanship with applied mathematical theory for lens design. Shortly after, chemist Otto Schott joined, bringing new optical glass formulations capable of correcting aberrations previously thought unavoidable.
That combination of physics, chemistry and industrial precision is what made Zeiss a global reference in optical science.
From that same lineage came some of the instruments that defined how we observe the sky: the large reflecting telescope Zeiss built for the Potsdam Observatory, and the world’s first optical planetarium, unveiled in 1923 at the Deutsches Museum in Munich. Today, the same division that manufactures photographic lenses and lithography optics for semiconductor production also develops the ophthalmic lenses people wear every day.
When we say these glasses carry a Zeiss-certified filter, that is what we mean: the same optical engineering standard that has photographed galaxies and built entire planetariums, applied to a €4.50 filter.
L’Atelier Óptica is also an official Zeiss Vision Expert certified centre in Madrid , one of the few independent optical boutiques to hold the highest level of Zeiss specialisation accreditation.
What ISO 12312-2 actually requires
For an eclipse filter to be considered safe, it must comply with ISO 12312-2:2015, adopted in Spain as UNE-EN ISO 12312-2:2015. Having the reference printed on the packaging is not enough: the standard requires the marking ( manufacturer, certification number, standard reference) to be permanently engraved on the filter itself, not as a label that can be printed onto any lens.
This is precisely where many products sold through online marketplaces in the run-up to an eclipse fail: items that show the ISO code on the box but have no real laboratory testing behind them. Spain’s National Geographic Institute explicitly warns that improvised filters, X-ray film, photographic negatives, smoked glass, stacked sunglasses , may reduce visible glare without filtering the radiation that actually damages the retina. The damage is painless, and symptoms may take hours or days to appear.
Where to buy certified eclipse glasses in Madrid
- Zeiss-certified filter, compliant with ISO 12312-2:2015
- PVP 4,50 €
- Available exclusively at our two central Madrid boutiques (not sold online)
L’Atelier Barrio de Ópera (Near the Royal Palace and Opera House)
Calle de Santiago, 8 · 28013 Madrid
Tel: 910 230 842
Lunes a viernes de 10:30 a 14:30 y de 16:30 a 20:30 · Sábados de 10:30 a 14:30
L’Atelier Barrio de las Letras (Near Prado Museum)
Calle de Moratín, 18 · 28014 Madrid
Tel: 910 295 536
Lunes a viernes de 10:30 a 14:30 y de 16:30 a 20:30 · Sábados de 10:30 a 14:30
Our team speaks Spanish, English and French at both locations. No appointment needed to purchase eclipse glasses.
The eclipse on 12 August
At sunset, the Moon’s shadow will cross northern mainland Spain and the Balearic Islands ( Galicia, Asturias, Cantabria, the Basque Country, Navarre, northern Aragon, Catalonia and the Balearics —)bringing a total eclipse, with totality between 20:26 and 20:33 local time. Outside that band, including Madrid, the eclipse will be partial, with up to 97-99% of the Sun covered.
Except during the brief minutes of totality within that specific zone, certified eclipse glasses are required at all times.
You can check the exact time and coverage percentage for your location at trioeclipses.es or the Spanish National Geographic Institute’s eclipse viewer.
Before 12 August
1. Check the exact eclipse time for your location at trioeclipses.es
2. Visit either of our boutiques to pick up your Zeiss-filter eclipse glasses. No appointment needed
3. Find a clear horizon to the west-northwest, the Sun will be very low at sunset
4. Don’t leave it until the last week, certified eclipse glasses sold out days before the event in previous eclipses
Frequently asked questions
Are eclipse glasses from supermarkets or Amazon safe?
It depends on the filter, not where they’re sold. What determines safety is whether the filter carries the ISO 12312-2 marking permanently engraved ,not printed on the packaging, and whether it comes from a verifiably certified manufacturer. When in doubt, choose a trusted source.
Can children use them?
Yes, provided an adult ensures the glasses are properly fitted and the child does not remove them while looking at the Sun. ISO 12312-2 does not distinguish between adults and children. The filter performs identically in both cases.
How long does totality last in Madrid?
Madrid falls outside the band of totality. The eclipse will be partial, with up to 97-99% of the Sun covered, still a remarkable sight, but one that requires certified glasses throughout the entire observation period without exception.
Can I use regular sunglasses instead?
No. No conventional sunglasses, regardless of darkness, meet the ISO 12312-2 standard. The transmittance difference between sunglasses and an eclipse filter is several thousand times.
Where can I buy eclipse glasses near me in Madrid?
At L’Atelier Óptica, an official Zeiss stockist in Madrid city centre — Calle de Santiago, 8 (Barrio de Ópera, near the Royal Palace) and Calle de Moratín, 18 (Barrio de las Letras, near the Prado). Is not available online. No appointment needed.
Do you ship eclipse glasses internationally or within Spain?
No. These glasses are only available in person at our two Madrid boutiques. If you are visiting the city before 12 August, stop by either location during opening hours.
Oficial Source: Trío de Eclipses — Gobierno de España / FECYT
