(USA TODAY) -- The biggest and best solar eclipse in American history is coming soon to a sky near you.
On Aug. 21, a total solar eclipse will be visible from coast to coast. It will be the first total eclipse visible only in the USA since the country's founding in 1776.
Here's everything you need to know about the spectacular event:
How can you safely view the solar eclipse?
The only moment it's safe to look at the eclipse is during the 2-3 minutes when the sun is completely behind the moon. Before and after that — during the partial eclipse — special eclipse glasses, or welder's goggles, must be worn. That's because the sun’s surface is so bright that if you stare at any portion of it, no matter how small, it produces enough light to permanently damage your retina. Our eyes never evolved to look at the sun without suffering severe damage. Regular sunglasses are also not safe to use.
Which eclipse glasses are safe?
If you buy eclipse glasses, be sure that they are made by one of the five companies the American Astronomical Society and NASA has certified as safe for use. The companies are American Paper Optics, the Baader Planetarium (in Germany), Rainbow Symphony, Thousand Oaks Optical, and TSE 17. They should all have the “ISO” (International Organization for Standardization) icon. The glasses also must have the ISO reference number 12312-2.
How many solar eclipse glasses are being sold?
Demand for the special glasses — which allow you to safely view the event — is fast and furious. American Paper Optics in Bartlett, Tenn., the company that produces the most eclipse glasses, is working speedily to churn them out. So far, the company has produced about 37 million glasses and is shipping out as many as 500,000 each day. The company had hoped to make 100 million of the glasses.
Can you take a photo of the eclipse with your smartphone?
Yes, but the quality may be rather poor, as smartphones were never designed for sun and moon photography. The best thing to do is to cover the camera lens with a solar filter during the moments before (and after) the total eclipse when the sunlight is still blinding. Though it may be OK for a few moments, it's not wise to point your smartphone camera at the brilliant, un-eclipsed sun for an extended period of time without putting a filter over the lens. A telephoto lens system is absolutely a must-have for quality eclipse photography with a smartphone. Most of the best shots you'll see related of the eclipse will be taken with professional digital cameras on tripods, or shot through a telescope.
What is a solar eclipse?
A solar eclipse occurs when the moon passes between the sun and the Earth. The moon appears to completely cover the disk of the sun. By blocking the sun's light, the moon casts a shadow that turns day into an eerie twilight here on Earth. Eclipses occur because of the special coincidence of the moon and the sun being the same size to our eyes. The sun is 400 times wider than the moon, but it is also 400 times farther away, so they appear to be the same size in the sky.
When is the solar eclipse?
When is the next solar eclipse?
The next total solar eclipse here in the U.S. will be on April 8, 2024, which will be visible from Texas to New England. More total eclipses in the U.S. will follow in 2044, 2045 and 2078. In other parts of the world, the next total solar eclipse will be visible in Chile and Argentina on July 2, 2019.
Are there any solar eclipse flights?
If you're worried about clouds ruining your solar eclipse experience Aug. 21, there is one surefire way to see the spectacle: From an aircraft that will fly above any pesky weather problems. Alaska Airlines will charter a flight over the Pacific so select passengers can see the eclipse from the sky. Some commercial flights will, by coincidence, be flying along the eclipse path: Alaska Airlines Flight 3382, Southwest Flight 1368 and Southwest Flight 1559.
Where are hotels still available?
Procrastinators, rejoice. Whether you're looking for a motel room or just a place to pitch your tent, you still have a few options for a place to stay across the country. One caveat: It'll likely cost you. One motel in Casper, Wyo., just raised its nightly starting rate for the event from $890 to $1,495. And some Airbnb's are going for more than $5,000 a night. You may just be plain out of luck in some places. Most, if not all, hotels in the Greenville, S.C., area are booked the Sunday before the solar eclipse.
What will the economic impact be for cities in the path?
Call it coast-to-coast ka-ching! Just 2-3 minutes of darkness during the Aug. 21 total solar eclipse is bringing in millions of tourist dollars from Oregon to South Carolina, as hotels, campgrounds, restaurants and museums enjoy a phenomenal boon to business. Nashville, the largest U.S. city entirely in the path of the total eclipse, estimates 50,000-75,000 visitors will stay overnight and spend a total of $15 to $20 million. More than 100,000 people are expected to visit Salem, Ore., and spend about $9 million. Charleston, S.C. says the event is so unusual they have no way to project the visitors or how much money the city will rake in.
Will schools be opened or closed for the eclipse?
Even schools are gearing up for the eclipse — by shutting down or ramping up lessons. Several school districts in the South have announced classrooms will be closed Aug. 21 for the rare solar eclipse, while others are incorporating the event into their curriculum. Many schools across the country will be closed regardless because of summer vacation. But school districts across the southern U.S. typically open earlier, forcing them to make a decision: Keep students in school or let them stay home.
Where could clouds ruin your view?
Based on historical weather conditions, both the Pacific and Atlantic coasts could see cloudy conditions. Increased cloud cover will also be possible as the eclipse travels east of the Mississippi River. Both Nashville and Columbia have a 44% chance of clear skies.
Folks in Idaho, Wyoming and Nebraska will have the best chance of clear skies. Casper, Wyo., has an 88% chance of clear skies on Aug. 21.
Will there be 'eclipse parties?'
Yes, the eclipse tourist hype is in full swing: Organizers of the Oregon SolarFest are calling it "a rare, mind-blowing cosmic experience," while Nashville promises visitors "a once-in-a-lifetime celestial event." Meanwhile, Carbondale, Ill., is promoting itself as the “Eclipse Crossroads of America," and Charleston, S.C., is planning a blues-and-barbecue harbor cruise during the eclipse.
How will public lands be affected by people wanting to see the eclipse?
Millions of visitors are projected to swarm the forests and mountains in states within the eclipse path of totality, right at the time wildfire danger and summer tourism is reaching its apex. The nightmare scenario is a wildfire breaking out while roads are clogged with cars and campgrounds filled with people. But there's also concern about thousands of people fighting for just a few open campsites, along with flip-flop wearing hikers attempting to climb dangerous mountains.
Could street lights hinder views of the eclipse?
For city dwellers, street lights may be a serious distraction from the rare astronomical event. Any light pollution will affect seeing the corona — which is easily visible during a total solar eclipse — especially for people interested in doing photography or astronomy. For casual viewers, the darkness during a total solar eclipse is comparable to a night with full moon. If you want to get a good look at the moon, you wouldn't want to stand near a street light.
Why are solar eclipses so rare?
It takes three celestial bodies (the sun, moon and Earth), all of which are on various orbital paths, to line up in the exact way at the right time to create an eclipse. On average, a total eclipse is visible from any one spot on Earth about once every 375 years. In the U.S., it takes about 1,000 years for every geographic location in the Lower 48 to be able to view a total solar eclipse. So you must be in just the right place at just the right time to observe a total solar eclipse.
Why is this called the 'Great American Eclipse?'
This is the first total solar eclipse that's only visible in the U.S. and no other country. It will be the first total eclipse visible only in the USA since the country was founded in 1776.
Why is the total solar eclipse only visible in the U.S.?
Eclipses are only visible in parts of the world at any given time. This one just happens to be in the U.S.
What time is the solar eclipse?
It depends on where you live. The eclipse will start on the West Coast in Oregon and trace a 67-mile wide path east across the country, finally exiting the East Coast in South Carolina. The total eclipse begins in Oregon at 10:16 a.m. PDT. (To be the first person on land to see the eclipse, be on the waterfront at Government Point, Ore., at 10:15:56.5 a.m. PDT.) The total eclipse will end near Charleston, S.C., at 2:48 p.m. EDT.
How long will the solar eclipse last?
At any given location, the total eclipse will last for around 2 or 3 minutes. But from the beginning of the eclipse in Oregon to the end of the eclipse in South Carolina, the eclipse will last about an hour and a half.
Where is the 'path of totality?'
The path, in which the moon's shadow sweeps across the Earth's surface, will cross parts of 12 states: Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina.
Some of the larger cities directly in the path include Nashville, Tenn.; and Greenville, Columbia and Charleston in South Carolina. Both Kansas City and St. Louis, Mo., are barely outside the path.
Smaller towns in the path include Salem, Ore.; Idaho Falls, Idaho; Casper, Wyo.; Grand Island and Lincoln, Neb.; St. Joseph and Columbia, Mo.; Bowling Green, Ky.,Clarksville and Murfreesboro, Tenn.; and Anderson, S.C.
When was the last solar eclipse?
In the U.S., it was on Feb. 26, 1979, in Washington, Oregon, Idaho, Montana and North Dakota, a day in which the weather was unfortunately "bleak." The August eclipse will be the first total solar eclipse that will be visible from coast to coast since June 1918. Elsewhere, the most recent total solar eclipse was in Indonesia on March 9, 2016.
How 'fast' is the eclipse?
The average speed of the moon's shadow as it crosses the U.S. is nearly 1,700 mph. That's over two times faster than a supersonic jet.
How many people will be able see the total eclipse?
An estimated 12 million people live within the path of totality. The number of people within just one day's drive of the totality zone is around 200 million.
What will I see during a total solar eclipse?
During a total solar eclipse, the disk of the moon blocks out the last sliver of light from the sun, and the sun's outer atmosphere, the corona, becomes visible. The corona isn't an indistinct haze; skywatchers report seeing great jets and ribbons of light, twisting and curling out into the sky.
What will happen during the total eclipse?
Plants and animals act as though night is falling, as flowers close up and birds return to roost. The temperature can drop 10 degrees or more.
Where will a partial solar eclipse be visible?
If you're not in the "path of totality," you'll still get a chance to see a partial eclipse, when only a part of the sun is blocked by the moon. A partial eclipse will be visible in all of North America, parts of South America, western Europe and Africa. While a partial eclipse is still cool, you won’t notice your surroundings getting dark.
Could this be the most-viewed eclipse ever?
Astronomy magazine says yes, basing this proclamation on four factors: 1) The attention it will get from the media; 2) The superb coverage of the highway system in our country; 3) The typical weather on that date; and 4) The vast number of people who will have access to it from nearby large cities.
Will traffic be bad on Aug. 21?
Yes, it could be one of the worst traffic days in U.S. history, some NASA representatives predict. Although about 12 million people live within the narrow band of totality, about 200 million reside within a day's drive of it. The agency has estimated that the population inside the path of totality may double on the day of the eclipse.
Do solar eclipses affect humans?
No, there's no evidence that eclipses have any physical effect on humans. However, throughout history, eclipses have been known to produce profound psychological effects. For millennia, they were sometimes interpreted as portents of doom by virtually every known civilization.
How can 'citizen scientists' participate in the eclipse?
NASA has many opportunities for amateur astronomers and lifelong learners to get in on the fun of doing science during the eclipse.
How are eclipses predicted?
Astronomers first must work out the geometry and paths of the Earth and moon as they orbit around the sun, mathematically figuring out the motions of each of the three bodies in three-dimensional space. Astronomers then feed the current positions and speeds of the Earth, moon and sun into a computer, programming it to calculate their future paths in relation to one another and what will be the view from the vantage point of us down here on Earth. Eclipses are specific predictions of where the three bodies will be at an exact time and place. Current eclipse forecasts are accurate to less than a minute in time.
What are some misconceptions about eclipses?
Here is a partial list of what total solar eclipses DON'T do: Emit harmful rays, affect pregnant women, poison food, predict bad events or foretell major life changes.
How many people have seen a total solar eclipse?
Fewer than 1 in 1,000 people has ever seen a total eclipse of the sun.
How many total solar eclipses are there each year?
There is one somewhere on Earth roughly every 18 months.
When was the first solar eclipse?
Solar eclipses have occurred for billions of years, but no one was here to see or record them. The earliest writings we have showing people paid attention to eclipses in any official way are around 5,000 years ago, based on some inscriptions on a monument in Ireland. Eclipses were also recorded in Ancient China, Babylonia, and Greece. In China, people would light fires or shoot arrows at the sun to try to make it catch fire again. After a total eclipse in 840, Emperor Louis of Bavaria was supposedly so terrified of the event that he died shortly afterwards.
What is an annular solar eclipse?
An annular eclipse occurs when the moon covers the sun's center, leaving the sun's visible outer edge to form a “ring of fire” or "annulus" around the moon.
What is a hybrid solar eclipse?
A hybrid eclipse shifts between a total and annular eclipse: At certain points on the Earth, it's a total eclipse, whereas at other points it appears as annular.
What is a lunar eclipse?
It's when the Earth gets in between the sun and the moon. The Earth's shadow is cast on the moon.
Sources: NASA, NOAA, Astronomy.com, AstronomyToday.com, Sky and Telescope, Space.com, "Get Eclipsed" by Pat and Fred Espenak.