Millions of people in eastern Canada and parts of the Atlantic coast will be able to see a rare solar eclipse on April 8th. But experts say you should only look up if you have proper eye protection.
Why is watching a solar eclipse more dangerous than looking at the sun on a normal day?
Dr. Philip Hooper, president of the Canadian Ophthalmology Association, says when people normally look up at the sun, its intense brightness can cause pain and cause them to quickly look away before damage can be done.
But when the moon begins to block the sun in the period leading up to a total solar eclipse, “the sun emits significant light energy, but we don’t perceive the pain. So it doesn’t last long enough to cause eye damage. You can keep looking,” says Hooper, who is also an associate professor of ophthalmology at Western University in London, Ont.
How does staring at the sun damage our eyes?
When you look directly at the sun, powerful visible and infrared rays are focused on the center of your retina at the back of your eye.
“It’s basically like taking a magnifying glass out in the sun on a normal day and focusing that light onto a piece of paper. It can get hot enough to burn the paper,” Hooper said. Ta.
The sun has the same effect. This is because the eye focuses its energy on a small area of the retina.
“The temperature of the cell in that area can actually become so high that the fluid inside the cell actually boils and permanently damages the cell,” he says.
Is it okay to just wear sunglasses to view the solar eclipse?
No, sunglasses don’t provide protection, Hooper said.
What if you stay indoors and look out the window?
Again, no. Windows has no protection.
Is it safe to view through a cell phone camera?
no.
“Eclipse or not, you should not look directly at the sun with the naked eye or with a camera or telescope without a (certified) solar filter. This can lead to irreversible eye damage. ,” says an eclipse safety video posted online by the Canadian Space Agency.
Pointing your phone’s camera directly at the eclipse can also have other effects.
“Remember, your phone camera has a lens, just like your glasses, and as soon as you open the shutter, light from the sun comes in,” said Alan I. Carswell, director of York University’s Alan I. Carswell Observatory. says Elaina Hyde. Toronto.
“At the very least, it’s possible that your camera could be damaged. Your phone can’t handle that light, so you won’t be able to see anything again.”
How can I safely view a solar eclipse?
According to the Canadian Space Agency website, special glasses with filters designed for viewing the eclipse will be required.
Hooper said these glasses need protection on the sides to keep the rays out.
Certified lenses are also required.
ISO 12312-2 certification must be printed on the glass. This means the glass meets international safety standards.
While wearing glasses, you can’t see anything unless you look at the sun.
“No matter how much bright light you’re exposed to in an indoor environment, if you put a really bright light on there, you can’t see anything. They’re pitch black. That’s how dark they are,” Hooper said. .
The American Astronomical Society says on its website that eclipse glasses should not be used if they have “scratches, holes, tears, or other damage,” and notes that glasses should be inspected before use. .
The association also states that children should always be supervised when using glasses during a solar eclipse.
Where can I get ISO 12312-2 certified glasses?
According to the Royal Astronomical Society of Canada’s website, free eclipse viewing glasses are available at many libraries, cities and school districts across Canada.
The American Astronomical Society has a list of companies and retailers in Canada and the United States that sell certified eclipse glasses on its website.
Several companies selling them in Quebec are listed on the Eclipse Quebec website.
What about welding glasses?
According to the Canadian Center for Occupational Safety and Health’s website, welding goggles come in a variety of shades, designated by a number.
Hooper said the minimum darkness needed to safely view the eclipse is the 13th floor.
“This is much darker than the welding glasses or goggles that welders typically use. And those aren’t widely available,” he said.
If I don’t have certified glasses, are there other options?
Another option for safe viewing is to build your projector so that it doesn’t look directly at the sun. It can be as basic as a projector made from a piece of paper or a box with pinholes that project light from the sun onto the sidewalk.
The Canadian Space Agency’s website provides easy instructions on how to make a projector using an empty cardboard box, white paper, aluminum foil, pins, tape, and scissors.
For instructions, see https://www.asc-csa.gc.ca/eng/youth-educators/activities/fun-experiments/eclipse-projector.asp.
-With files from Sonja Puzic
