Select a city and drag the moon's shadow to discover the amount of coverage at various times. Vancouver Smithers Edmonton Calgary Regina Winnipeg Churchill Toronto Ottawa Quebec City Halifax St. John's

Protect your eyes

While fascinating to witness, it’s dangerous to look directly at an eclipse without proper protective eyewear.

Looking at the sun anytime can be damaging because it outputs more energy than our eyes can handle. But in the event of an eclipse, the effect can be even more intense.

When it’s dark, our pupils dilate to take in more light. If you were to look at the sun immediately after an eclipse, when the sun came back into view, your widened pupils would become flooded with bright light, which can cause serious damage — it only takes a second.

It’s only safe to look at the sun during totality, which will last two minutes and 40 seconds on Aug. 21. Be sure to check exact times of totality if you’re lucky enough to be in the path.

To protect your eyes, wear special eclipse glasses, which you can get at many local museums and science centres, or order through websites like the Royal Astronomical Society of Canada. NASA says to make sure the glasses have certification information, with a designated ISO 12312-2 international standard. Don’t use them if they’re bent, damaged or more than three years old.

NASA’s Jet Propulsion Laboratory also has instructions for making a pinhole eclipse viewer.

If you’re viewing through a telescope or taking pictures, make sure to get special lenses for those, too.

Disclaimer: The images and animations in this feature are not to scale, and some images differ from what you may see on the day of the eclipse.