Everything you need to know about August's eclipse of a lifetime

A primer on why this one is a biggie and where to try to catch it!

A primer on why this one is a biggie and where to try to catch it!

The solar eclipse will take place on Aug. 21. (Getty Images/iStockphoto)

On the morning of August 21, a dark shadow will cross over North America. The temperature will drop, people will see stars and a fiery halo will appear in the sky.

No, it's not the apocalypse – it's a once-in-a-lifetime solar eclipse.

"We happen to be at a very lucky place in the universe and a very lucky place in earth's history and time to be able to see this complete blocking out of sun," said Jesse Brydle, a science educator at Science World British Columbia. "It's a very rare occurrence and it happens for a very brief moment."

In fact, the complete solar eclipse will last between just two minutes and two minutes and 40 seconds in parts of the United States. In Canada, we won't see the complete solar eclipse at all (we're too far North) but residents of Western Canada will see about 85 per cent of a full eclipse, Brydle said.

Still, a two-minute eclipse? What's all the hype about? The answer: an eclipse of this magnitude – it will travel from coast to coast across the United States – hasn't been seen since 1918, according to NASA.

To prepare, we asked Brydle everything you could want to know about how to make the most of the upcoming eclipse.

What is a solar eclipse?

A solar eclipse is an astronomical phenomenon that involves the moon passing between the sun and the earth, casting a shadow onto the earth. Solar eclipses happen around two to five times a year, but typically only part of the sun is covered. About every 12 to 18 months, a full solar eclipse is visible from some part of the world, but it's often missed because the shadow is cast over the ocean.

The fact that we're able to see a full solar eclipse – called "totality" – at all at this point in history is pure luck: the moon is slowly moving farther away from the earth, and right now, the moon is exactly 400 times closer to earth than the sun and 400 times smaller than it. In the distant future, the moon will be too far away, appearing too small, to completely block the sun.

What will people see during the eclipse?

It depends where you are. If you're in a place like Vancouver or Victoria, a dark shadow will be cast across the earth and 85 percent of the sun will be blocked by the moon. In Halifax, there will be more sun, with just less than half of it being covered by the moon, and in the far north, only around three per cent of the sun will be covered.

In the U.S., those under the direct path of the total eclipse will see a far more spectacular sight. The sky will go dark, stars will appear and the sun's corona, the ring of hot, fiery-looking solar activity surrounding the sun, will be on full display.

Where are the best locations to watch the eclipse?

Sorry, Canada, you won't be able to see the complete eclipse from anywhere. To witness "totality," you must be within a 110-kilometre-wide band that moves from northwest to southeast across the U.S., starting in Oregon and ending in South Carolina. Head to Hopkinsville, Kentucky, where the full eclipse will last two minutes and 40 seconds, the longest period of totality in North America, or go to an eclipse festival. But be warned: some hotels have been booked up for years.

When will it take place?

In the westernmost parts of Canada, it starts just after 9AM PST and ends at 11:30AM. In the easternmost part of Canada, Newfoundland, it starts around 3:30PM. NDT and ends around 5:30PM. In most Canadian locations, the partial eclipse will last two and a half hours. To get specific details on when it will pass through your community, visit the website Time and Date.

How can people watch it safely?

The sun's UV rays are powerful enough to cause something akin to a sunburn on the eye's retina. Unless you want to fry your eyes, wear solar viewing glasses. Buy glasses from your local science centre – at Science World British Columbia they're selling for $2 – or make a DIY pinhole projector, which is basically a box with a hole in it that projects an image of the sun.

What if it's a cloudy day?

Two options: move to a location that isn't cloudy or – (well, it's true!) – or, watch the whole thing on NASA's live stream.

Katrina Clarke is a Vancouver- and Toronto-based journalist who writes about relationships, health, technology and social trends. Find her on Twitter at @KatrinaAClarke.