August 21 is a big day in the American celestial calendar: the 2017 solar eclipse. Referred to by some as the “Great American Eclipse,” its track across the entire continental United States gives millions the opportunity to see the sun disappear for a few minutes — in some places, completely — behind the moon.
What makes the 2017 solar eclipse all the more special is it’s a total eclipse, where the sun is blocked out more completely than during a more common annular eclipse. Such a thing hasn’t been viewable from American soil in 38 years, so be sure to take a picture! It will be one of the most impressive celestial events of the year. So why should you be excited about this event? Read on and we’ll explain.
Why do solar eclipses happen?
Solar eclipses occur when the moon passes in front of the Sun, blocking out its light. While the moon is only a minuscule fraction of the size of the Sun, the Sun is 94 million miles away from us, and this allows the moon to block out the Sun’s rays across a small fraction of the Earth’s surface.
You might be wondering why solar eclipses are so rare. This is due to two factors. First, the moon must be in the “new moon” phase, which means it is between the Earth and the Sun. Because of this, we see the “dark side of the moon,” and the moon appears invisible. But with new moon phases happening every 29.5 days or so, why aren’t eclipses happening just as frequently? You can thank the tilt of the moon’s orbit with respect to Earth for that.
There’s about a five-degree difference at play, which explains why the moon’s position in the sky seems to change daily (this also has to do with Earth’s seasonal orbital wobbles, which explains why we have seasons). This means that during most new moons, the Moon’s shadow either falls above or below the Earth’s surface.
But generally, two times a year these two orbits line up just right, and an eclipse occurs. If you’re lucky enough to see it, it’s a beautiful sight. And if you’re an astronaut, you’re in for a treat; watching the eclipse from the moon is completely different.
What’s the difference between an “annular” and “total” solar eclipse?
Solar eclipses come in two forms, annular and total. The difference depends on the orbit of the moon. In space, orbits are not a perfect circle: instead they have some degree of eccentricity, which is a measure of how much the orbit deviates from that perfect circle. This eccentricity also governs the magnitude of the eclipse itself. You can also see this concept at work throughout the year as the moon appears to grow and shrink in size in the night sky.
Most of the time the moon is far enough away that it doesn’t cover the sun completely, allowing for a ring of sunlight to come through. While light is greatly reduced, there still is enough that areas in the path of totality are basked in eerie twilight. With total eclipses, it is different.
In a total eclipse, the moon blocks out the solar disk completely, leaving a fibrous halo. What you’re seeing here is the sun’s corona — one of the few times it is visible on the Earth’s surface to the naked eye. Bright stars may become visible, crickets may start chirping, and you might even experience a sudden (but small) drop in temperature. For a total eclipse, the moon must be close enough to block out the entire solar disk, which makes them less common than annular ones.
In either case, totality lasts only for a few minutes, although the process to and from totality takes several hours.
What should I expect from the 2017 solar eclipse?
This depends greatly on where you are. Every U.S. state will see some percentage of the Sun disappear, with the Lower 48 seeing the Sun at least 55 percent obscured. The first spot to see totality in the U.S. from the 2017 solar eclipse will be just north of Newport, Oregon at about 10:15 a.m. PT. (Pack a bag of eclipse gear and get going!) From there, it will race east and southeastward, exiting the U.S. coast at 2:49 p.m. local time at Cape Romain, South Carolina.
(Editors note: while it seems like a long time, we’re using local times. The ‘path of totality’ will actually make its way across the entire Lower 48 in just 94 minutes!)
Altogether, 14 states will be in the path of totality, with those passing closest to the center of that path experiencing generally around two and a half minutes of darkness. Carbondale, Illinois will take the cake though: the city is closest to the point of greatest totality, and will see the sun eclipsed for 2 minutes, 42 seconds!
Where are the best spots to catch the 2017 solar eclipse?
What, watching the eclipse on Twitter isn’t good enough for you? That’s going to depend on your personal preference, but we’ve attached an interactive map to give you a better idea of where to go and get the best view.
It’s hard to say in advance where the weather will be the best. One thing you’re going to want to watch for is cloud cover. Any kind of visual obstruction between you and the sun is going to affect how you’ll be able to see the event.
A rule of thumb is to stay away from the coasts. Marine layer clouds typically form overnight, reaching their peak around sunrise. In terms of the 2017 solar eclipse and its timing over the West Coast, there will be about six hours for daytime heating to help dissipate this layer. That should be sufficient unless the marine layer is quite thick.
Our suggestion? Choose an inland location — there’s a better chance that you’ll escape the clouds and have an overall better viewing experience. But like we said, we unfortunately can’t be specific just yet.
If you want to be first, you’ll want to head out to a spot between Depoe Bay and Lincoln Beach (you might see some DT folk there too — our HQ is only a two-hour drive away), and hope those marine layer clouds we talked about don’t pose a problem. Plenty of places look like good spots to see the eclipse that day, however. Locations further inland, like Madras, will likely have much better weather, as well as much of the Intermountain West.
You might want to check out Casper, Wyoming, which will see 2 minutes and 26 seconds of eclipse starting at 11:42 a.m. local time. Seven minutes later, totality will pass over the Sandhills of western Nebraska, which is also likely to have prime viewing weather (read: no clouds).
If more urbanized viewing is your preference, one of best cities to see the event is St. Joseph, Missouri. The city is right on the centerline and will see 2 minutes and 39 seconds of totality beginning at 1:06 p.m. local time. The city is taking advantage of this with a large viewing party planned at the Rosecrans Memorial Airport.
If that’s not enough for you, you might want to head to Illinois instead. The city of Carbondale will enjoy the longest period of totality at about 2 minutes, 42 seconds starting at 1:20 p.m. To commemorate, the city is actively promoting several events in and around eclipse day — including the fact that they’ll be in the path of another total solar eclipse just seven years later!
Richard Bouhet/AFP/Getty Images)
Another interesting spot to check out the event might be Nashville, Tennessee. While not directly in the path, the Music City will still enjoy 1 minute and 57 seconds of totality starting at 1:20 p.m. local time — and there’s a lot to do to make a vacation out of it.
Other good possibilities might be the Great Smokey Mountains National Park in North Carolina, with about 1 minute and 17 seconds of totality at 2:35pm local time, or Charleston, South Carolina, whose residents will see 1 minute, 33 seconds of totality starting at 2:46pm local time as the moon’s shadow moves off the East Coast.
How do I view the solar eclipse?
This is possibly the most important section of this entire story to read, because if you don’t follow it, you risk doing a good deal of damage to your eyes. At no time during or after totality should you look directly at the sun without protective eyewear. Also, don’t think regular sunglasses will protect you either — they won’t.
NASA recommends “eclipse glasses” from three manufacturers: Rainbow Symphony, American Paper Optics, and Thousand Oaks Optical. These have met a particular standard, ISO 12312-2, which provides sufficient protection from harmful light.
The space agency also encourages viewers to ensure that their eclipse glasses have the manufacturer’s name and address printed somewhere on the product, and that the eyewear is not older than three years. Of course, if your glasses have scratched or wrinkled lenses, you shouldn’t use those either. And be warned, even the darkest of ordinary sunglasses are not a satisfactory replacement for eclipse glasses. You can get a pair of your own eclipse glasses from one of more than 6,800 libraries across the U.S. who are distributing safety-certified glasses.
“While NASA isn’t trying to be the eclipse safety glasses ‘police,’ it’s our duty to inform the public about safe ways to view what should be a spectacular sky show for the entire continental United States,” said Alex Young, associate director for science in the Heliophysics Science Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s important that individuals take the responsibility to check they have the proper solar eclipse viewing glasses. With the eclipse a month away today, it’s prudent to practice ahead of time.”
If you can’t get these glasses in time, you can also use a pinhole projector. “With this method, sunlight streams through a small hole — such as a pencil hole in a piece of paper, or even the space between your fingers — onto a makeshift screen, such as a piece of paper or the ground,” NASA explains. “It’s important to only watch the screen, not the Sun. Never look at the Sun through the pinhole — it is not safe.”
And finally, you could also choose to watch the eclipse by way of NASA Television, whose live program Eclipse Across America: Through the Eyes of NASA will offer real-time coverage of the event from coast to coast with plenty of unique footage. If you yourself are photographing the 2017 solar eclipse, do not view it through the viewfinder during the partial portions of the eclipse.
While on the topic of eclipse photography, we suggest you check out Lee Filter. The company has produced a filter specially made to remove infrared rays that may damage your camera. Lee Filter says to use the filter when shooting during partial phases, but you should remove it during totality.
The old pinhole projector is another way to view the eclipse. You can learn how to build a pinhole viewer here.
Another way to view the eclipse is via live-stream. NASA’s by far is the most comprehensive, with views from 3 aircraft, 11 satellites, and 50 high altitude balloons. Volvo plans its own (but much smaller) live-stream, filmed entirely from a fleet of its XC60 SUVs placed along the eclipse path.
I’ve heard about another U.S. total solar eclipse in 2024? What gives?
While it has been 38 years between the last total solar eclipse in the U.S., the country will be treated to yet another total eclipse in just seven years, on April 8, 2024. This eclipse will travel a different path, traveling from south central Texas to the northeast U.S., including portions of southeastern Canada.
This eclipse will be special due to its length of totality. In north Central Mexico, totality will approach four and a half minutes. Even still, places in the U.S. along the path will see at least 3 minutes and 20 seconds of totality, with many southern locations exceeding four minutes.
If you miss the 2017 version, be sure to catch the one in 2024, or an annular eclipse the year before on October 13. After that, the next total solar eclipse in the U.S. isn’t until 2044.
We’ll continue to update this story as the event gets closer. Until then, ask your questions or tell us what you or your town might be doing for the 2017 Solar Eclipse so that we can answer them for you and share the events with others!
Update: NASA has a few safety tips for eager viewers of next month’s eclipse.