On Saturday, August 11, many of us in the northern hemisphere will be treated to a partial solar eclipse.
Solar eclipses happen when the moon passes between the and the earth, so that the moon’s shadow falls across the earth. Of course, since the moon is smaller than the earth, the moon’s shadow can only cover a relatively small area of the Earth. But for people who can see it, during a total solar eclipse the moon’s shadow will cover the earth, blocking out the sun’s light. Eclipses don’t last long — they can be as short as thirty seconds, or seven minutes at the longest — but they are awe-inspiring.
What’s happening on Saturday is not a full eclipse. Rather, it’s a partial eclipse. The moon will pass in front of the sun, and it will cast a big shadow — but it won’t fully block out the sun.
Still, it’s a sight well worth seeing. Here’s what you need to know about how to see the partial eclipse:
1. The Eclipse Starts At 4:02, As the Moon Begins to Cross in Front of the Sun
At 4:02 eastern time, the moon will start to slip in front of the disk of the sun. But in most places, the full spectacle of the eclipse will be best seen around 5:45.
Unfortunately, the eclipse won’t really be visible in the United States. But it will be visible in Greenland, Iceland, northern Europe, most of northern Russia and part of northern China, and even part of northern Canada.
For those of you in Canada, here is a useful table with viewing times for different regions.
2. Saturday’s Eclipse Is Expected To Be The Most-Watched Eclipse of 2018
Saturday’s eclipse won’t be visible for people living in the United States, or in the southern parts of Canada. But it will be visible for people in parts of northern Canada, Russia, northern China, and northern and eastern Europe. All in all, this will be visible to a huge swath of people — and the eclipse is expected to be the most-watched eclipse of the year.
This interactive graphic lets you figure out exactly how, and where, you can watch the upcoming eclipse. Just click on the map, and it’ll tell you whether the eclipse is visible from that location. It’ll also tell you how long the eclipse will be visible, and at what time. Here it is.
You can also see video showing the eclipse’s progression across the northern hemisphere, here.
And here’s a great animation showing you how the moon’s shadow will spread across parts of the earth.
3. Whatever You Do, Don’t Try to Watch The Eclipse With Your Naked Eyes
Eclipses are breath-taking, awe-inspiring events. But if you don’t take proper precautions, they can also be dangerous. Looking at an eclipse with your naked eyes can cause lasting eye damage, because the transition from darkness (during the eclipse) to bright sunlight (as the eclipse ends) is very sudden. This means that your pupils are fully dilated and your eyes aren’t defended against the sun’s rays.
So — if you want to watch the eclipse, use a pair of eclipse glasses, or try the pinhole projection method of watching the eclipse. The pinhole method allows you to project the image of the crescent sun onto any surface — the simplest way to do it is to create a hatched shadow using your fingers. The image of the crescent sun will appear in the space between your fingers’ shadows. You can read more about that, and other forms of pinhole projection, here.
4. Saturday’s Eclipse Will Be The Last Eclipse of 2018
For those of us in the northern hemisphere, Saturday will be our last chance to see a solar eclipse this year. 2018 didn’t have a total solar eclipse, the way that 2017 did. But for those of you who like to plan ahead, here’s a list of all the solar — and lunar eclipses that are coming up in the next few years.
In January of 2019, there will be a partial solar eclipse visible in parts of the Asia-Pacific region.
There will be a lunar eclipse visible in Europe, Asia, Africa, North America, South America, Pacific, Atlantic, Indian Ocean, and the Arctic later in January as well. During a lunar eclipse, the Earth blocks the sun’s light from reaching the moon, so that the only thing lighting up the moon is refracted light from the earth. This makes for a spectacular sight, as the moon looks reddish and a bit supernatural. A fully eclipsed moon is sometimes also called a blood moon.
In July 2019, there will be a total solar eclipse visible in the southern parts of North America, much of South America, and the Pacific.
You can find a chart listing all the upcoming eclipses here.
5. Astronomers Classify Solar Eclipses Into Four Categories: Complete, Partial, Annular, and Hybrid
Saturday’s solar eclipse will be a partial eclipse, which is sometimes described as the moon “taking a bite” out of the sun. The sun isn’t completely obscured. Instead, just a piece of it — a bite — is blocked off by the moon.
But there are three other categories of eclipse. The total eclipse is what many of us in North America experienced back in August of 2017, when the moon passed in front of the sun and darkened the earth for a few amazing moments.
An annular eclipse happens when only the sun’s center is covered by the moon. The leaves the sun’s outer edges shining uncovered, so that you can see a ring of the sun around the shadow produced by the moon. The word “annular” comes from the Latin for “ring.”
Finally, a hybrid eclipse is a sort of combination of the total eclipse and the annular eclipse. A hybrid eclipse is an event which can be seen for a few parts of the Earth at once. From one part of the earth, it will look like a total eclipse; from another part of the Earth, it will be seen as an annular eclipse. You can find more about the categories of eclipses here.