Excitement abounds for the solar eclipse this Monday, August 21, when the moon will briefly pass between the Sun and the Earth. So-called “total eclipses” such as Monday’s offer a rare opportunity to view the full majesty of our most visible celestial neighbours, if only briefly.
But if eclipse-gazing is on your schedule, it’s important to take the necessary precautions to ensure you’re doing it safely. This is especially true for Canadians, who aren’t in the “path of totality,” a narrow band of geography encircling the globe where you can observe the moon as it completely obscures the Sun. Instead, Canadians and others outside the path will witness a partial eclipse. Even at peak alignment during a partial eclipse, the Sun will not be completely blocked.
Most of us, in other words, will still be subjected to the Sun’s powerful solar radiation. Staring directly at the Sun during a partial eclipse can damage your eyes. Whether it’s a held glaze or a quick glimpse, it should be avoided entirely.
The retina, the light-sensitive tissue housed at the back of the eye, is incredibly sensitive. This is why vision is so detailed. When the light-sensing cells in the retina—called “photoreceptors”—are subjected to an abundance of UV radiation, they can be damaged, sometimes permanently, resulting in “solar retinopathy.” Many of those living with blinding eye diseases such as retinitis pigmentosa experience the gradual degeneration of these cells and the associated degradation of vision. They know how valuable those cells are. And there’s a lot of science being pushed forward at the FFB to find ways to repair or replace damaged or missing photoreceptors, such as Dr. Bernier’s incredible work to turn stem cells into sheets of cone photoreceptors.
How are some tips to enjoy Monday’s eclipse while also protecting those precious cells:
- Use a pair of ISO-approved glasses or a handheld viewer that meets international safety standards. The appropriate device should bear the label “ISO 12312-2.” You can consult the American Astronomical Society’s list of approved vendors.
- Turn eclipse-watching into a fun DIY project by making a pinhole viewer with a cardboard box, paper, scissors, aluminum foil, a pin, and tape. The Canadian Space Agency has instructions for making one.
- NASA has an “Eclipse 101” guide for safe eclipse-gazing, including information on telescopes, camping, car safety, and more.