This Wednesday, August 12, a partial solar eclipse will be visible in France in the early evening.
On the eve of the event, protective glasses, essential for observing the eclipse safely, are in stock. out of stock at many pharmacists and opticians.
On social networks, Internet users believe that they can do without protective glasses and solar filters, equipment usually used to photograph eclipses in a secure manner.
Tempted by the D system, these Internet users announce on the X network and Facebook that they have handcrafted their own protective equipment.
The France 24 Observers editorial staff showed these devices to experts: they underline their dangerousness. Éric Lagadec, astrophysicist at the Côte d’Azur Observatory, warns: “My message is always clear: never tinker unless you are an expert.”
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Photograph the eclipse through a radio? “Definitely not to do”
On Facebook, an Internet user asks the following question: “Can the black of a radio be used to make a filter for the sun and the eclipse?”
Lacking time to find a suitable filter for her camera, the Internet user presents what she calls her “DIY”, which she wishes to use to photograph the solar eclipse:
“I have a UV filter and a glare cover. I cut out an old x-ray and stuck it between the two, will that work?”
This device presented on August 10, 2026 on Facebook by an Internet user to photograph the eclipse risks damaging her camera. Through an optical viewfinder, photographing the eclipse can damage eyesight. © Facebook
This montage is “definitely not to be done”, says Éric Lagadec.
In general, for the observation of an eclipse, radio films are “formally not recommended”, insists Florent Deleflie, researcher at the Space Time Laboratory (LTE) at the Paris Observatory-Université Paris Sciences et Lettres (PSL) and president of the Arras Scientific Groups. “A radio is not going to completely filter out the wavelength of light. If it’s UV, that light is going to get through and cause damage.”
The researcher adds:
“If we converge light rays on a camera, its sensor will be degraded or even burned.”
Such a device could also be dangerous for the vision of the person using it, if it is a reflex camera. As explained RMCSLRs have a viewfinder with a mirror system that reflects light into the photographer’s eye.
If the device is not equipped with sufficient protection, such as solar filters or ND100000 which block infrared and ultraviolet rays, the effect will also be “destructive” for the eyes, warns RMC.
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The glass of a solder mask? When in doubt, “avoid”
Another Internet user suggests as an alternative to protective glasses “the glass of a welder’s mask”, an opaque and tinted glass which protects vision against strong light during welding work. For his “astronomer’s DIY”, the Internet user mounted a soldering glass on a pair of binoculars.
This installation of soldering glass on a pair of binoculars published on August 10, 2026 on Facebook can be dangerous if the glass does not have a sufficient tint to protect vision against sunlight. © Facebook
Theoretically, a welding mask, if it has a lens with a tint “above 14”, estimates Éric Lagadec, can be sufficient protection for observing the eclipse. However, believes the astronomer, “it’s a bad idea. How can we be sure (of the level of protection of the glass) if we are not a specialist? We risk irreparable damage to our vision.”
If it is not equipped with sufficiently protective glass – the level of tint is not specified in the post – the device presented by the Internet user of binoculars behind the glass of a soldering mask could even amplify the damage caused by an insufficiently protected observation of the eclipse, estimates Éric Lagadec.
“It is possible to cook meat with the light coming from an observation telescope pointing at a solar eclipse”, illustrates Florent Deleflie to describe the power of a solar ray amplified by an observation instrument.
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What are the safe ways to observe the eclipse?
Florent Deleflie rules out other unsafe methods of observation, such as the use of “photo negatives”, which are also insufficiently protective, or observation with the naked eye, which can be very dangerous. “Unlike the sunset that we like to watch, the eclipse sun arrives too high in the sky (and diffuses radiation that is too powerful for observation). So no direct observation without protective glasses,” insists the researcher.
French authorities therefore recommend the use of “protective glasses specifically designed to be able to observe the sun by filtering 100% UV” and certified “ISO 12312-2”.
The making of an eclipse box. © French Astronomical Association
“Observing the sun in projection” is another safe way to admire the eclipse, adds Éric Lagadec.
The French Astronomical Association therefore suggests building an “eclipse box” or pinhole camera which allows the sun to be observed safely: “It simply consists of a support with a hole through which the light passes to form an image projected on a screen”, explains the association.
