You don't have glasses for the eclipse? This is how you can see it safely with a box
A scientist from the state advisory committee proposes a homemade projection system especially indicated for children
PalmaRunning out of certified glasses does not mean you have to miss out on the total solar eclipse. David Galadí-Enríquez, coordinator of the Scientific and Advisory Commission of the Eclipse Trio, proposes a "much safer and more fun" alternative, especially recommended for children: building a pinhole camera with a cardboard box.
This system is not used to look at the Sun directly, but to observe its projected image inside the box. This way, you can follow the Moon as it covers the star without exposing your eyes to solar radiation.
How is the pinhole camera built?
To prepare the device, the template disseminated by the Diputació de Pontevedra must be printed in A3 format and the box assembled following the instructions included in the document.
Once built, the box must be oriented towards the Sun until the image of the star appears projected inside. The observer must look exclusively at this projection through the opening provided for this purpose.
The essential rule is never to look directly at the Sun or observe it through the hole where the light enters. The opening should only allow solar rays to penetrate the device and project the image onto the inner surface.
Galadí-Enríquez assures that, if assembled and used according to the instructions, this projection system is a "totally safe" option for contemplating the development of the eclipse.
Click here to download the template in PDFApproved glasses have sold out
The alternative comes after certified eclipse-viewing glasses have sold out in numerous pharmacies and opticians in Palma over the last two weeks.
Some establishments have even put up signs to inform customers that they are out of stock and to slow down the constant arrival of clients and the phone calls from people still trying to get them.
According to the workers consulted, the first orders arrived in June, but demand has increased exponentially since Monday. Stocks have run out both in the establishments and in some of the warehouses that supply them.
An alternative for families with children
The camera obscura can be especially useful for families like Maria Magdalena's, who decided at the last minute to watch the eclipse and could no longer get approved glasses.
“We wanted to watch the eclipse on television because we have a small child and we are concerned about the dangers to eyesight,” she explains. Faced with a lack of glasses, she was looking for “homemade options with cardboard boxes, what they call crafts,” but she wanted to make sure they were suitable for children.
The projection system allows the little ones to follow the evolution of the phenomenon without having to look directly at the Sun. In any case, adults must supervise both the assembly and the use of the box.
Brief exposure can damage the retina
The Ministry of Health warns that direct exposure to the Sun without protection, even if brief, can cause irreversible damage to the retina. These lesions do not always cause immediate pain and symptoms may take hours to appear.
Conventional sunglasses, X-rays, tinted glass, photographic filters, and other homemade systems do not offer adequate protection. To look directly at the eclipse during the partial phases, only specific solar observation glasses that comply with the ISO 12312-2 standard and are in perfect condition should be used.
The phenomenon should not be viewed with binoculars, telescopes, cameras, or other optical instruments that do not have a specific solar filter placed in front of the lens. Approved glasses do not protect if used to look at the Sun through these devices, because the concentration of light can deteriorate the filter and cause immediate serious eye damage.
What symptoms should alert us?
Lesions caused by direct observation of the Sun can cause a dark spot in the center of the visual field, blurred vision, deformation of shapes, or alterations in color perception.
If any of these symptoms appear after the eclipse, you should avoid continuing to expose your eyes to intense light and seek medical attention. Not feeling immediate pain does not rule out that a retinal injury has occurred.
The dark chamber avoids direct observation of the star and offers a simple alternative for people who have not been able to get glasses. The essential condition is to follow the assembly instructions and only contemplate the image projected inside the box.
