You probably already have your glasses ready for the solar eclipse on August 12. However, for those who want to observe this astronomical phenomenon more closely, these may fall short. For this, binoculars and telescopes are a great option to appreciate all its phases, as long as they are accompanied by an essential accessory to protect your eyesight: a solar filter.
But not just any filter will do. As with plastic or cardboard glasses, it is important that it has the ISO 12312-2:2015 certification. That is why, from EL PAÍS Escaparate we have selected this certified solar sheet so you can enjoy the eclipse calmly and without missing any detail.
Observe the eclipse in detail, but protect your eyesight
As it is the first total solar eclipse visible from Spain in over a century, it is normal to want to take advantage of the occasion to observe it in the best possible way. But do not forget the following: although binoculars and telescopes offer a better view of what is happening in the sky, they do not work as protection against the Sun. In fact, they act like a giant magnifying glass and concentrate more sunlight. Therefore, if used without the proper filter, they can cause serious eye damage.
This solar sheet only lets through 0.000167% of visible light, in addition to filtering UV-A and UV-B radiation, and almost all infrared rays. In this way, it meets the requirements, including the ISO 12312-2:2015 standard, to safely view the eclipse. “I experimented with photos of the Sun and it works well. You can see sunspots and everything”, comments a user about the sharpness this filter offers.
It is a cuttable filter
Whether it is a telescope, binoculars, or a camera, each has a lens of different size. That is why, when placing a filter, it is advisable to choose the right size to avoid sunlight entering. A relevant aspect of this silver and black polymer sheet is that, besides having dimensions of 150 x 150 millimeters, it can be cut to fit different devices.
How is it placed?
At this point, the next step is to mount the solar filter on the device. The process is easier than it seems and only requires a few materials to install it on binoculars or a telescope. “It is easy to work with to adapt it to the camera lens and binoculars, and you see the Sun perfectly”, adds another buyer. Next, we explain how to do it step by step:
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- After measuring the diameter of the lens, cut a cardboard ring that will serve as support for the sheet. The inner hole must have the same diameter as the lens, while the edge must be at least one centimeter wide.
- Once this is done, cut the sheet. Using the cardboard ring as a reference, cut it two or three centimeters larger. Special care must be taken not to wrinkle it.
- It is time to join the two pieces. The cut sheet must be fixed to the cardboard support with adhesive tape. The attachment must be firm to prevent it from sliding.
- The black side of the filter should face the device and the silver side outward. With this, just place it on the front of the lens and check that there are no scratches or other types of damage.
Frequently asked questions about this solar filter
Are other sizes available?
Yes, on e-commerce you can choose between three sizes: 100 x 100, 150 x 150, and 210 x 210 millimeters.
What is the density of the sheet?
It has an optical density of OD 5.8.
How many times can it be reused?
The filter can be reused as long as it is kept in good condition. It is recommended to store it in a cool place and, before each use, check that it has no damage. If it shows any deterioration, it must be replaced with another.
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*All purchase prices included in this article are updated as of August 2, 2026.
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