At a Glance

A total solar eclipse will cross the United States on Aug. 21.It will be the first total eclipse in the U.S. in four decades and the first coast-to-coast eclipse in a century.Scientists offer suggestions on how to best view this once-in-a-lifetime event.

In just six months, Americans will have the opportunity to experience the in nearly four decades.

On Aug. 21, the "Great American Total Solar Eclipse" will mesmerize Americans across a 70-mile path from coast to coast, including states from Oregon to South Carolina.

Accordingto astronomerJay Passachoff of Williams College in Massachusetts, people lucky enough to be in the path of the total eclipse are in for a unique and unforgettable experience.

"It's a tremendous opportunity," Pasachoff . "It's a chance to see the universe change around you."

For about two minutes, the moon will completely block the sun in the 70-mile path, turning day into an eery, dark twilight. Even stars will become visible. The event from start to finish will take about three hours.

The path of the Aug. 21, 2017 total eclipse of the sun.

(Fred Espenak/NASA GSFC)

First Total Eclipse in Four Decades

The last time a total solar eclipse darkened the U.S. mainland was on Feb. 26, 1979.

What makes next year's eclipse even more unique is that it will be the first total eclipse that will be "readily available to people from coast to coast," Pasachoff said.

That path goes from the Oregon coast through Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina.

Space.com's columnist Joe Rao notes that 12 million people or so live within the narrow viewing band, but there are another 220 million who reside within a day's drive of it.

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Pasachoff said the event is so unique and memorable that he advises people to make the journey to the narrow path and experience this amazing celestial event.

"Though the rest of the continental U.S. will have at least a 55 percent partial eclipse, it won’t ever get dark there, and eye-protection filters would have to be used at all times even to know that the eclipse is happening. The dramatic effects occur only for those in the path of totality," Pasachoff said in a statement.

"If you are in that path of totality, you are seeing the main event, but if you are off to the side — even where the sun is 99 percent covered by the moon — it is like going up to the ticket booth of a baseball or football stadium but not going inside," he added.

How to Watch Safely

According to exporatorium.edu, no one should ever view the sun with the naked eye or by looking through optical devices such as binoculars or telescopes.

One of the best ways to view an eclipse is with a pinhole camera. NASA's Jet Propulsion Laboratory has a great explanation on how to make one .

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Exploratorium.edu also has some other great ideas on how to safely view the eclipse on its

For more precise details on the path and where to best watch the eclipse state by state, check out eclipse2017.org's .

MORE ON WEATHER.COM: Solar Eclipse, May 10, 2013

Sydney, Australia

A girl adjusts a telescope to focus the reflected image of a partial solar eclipse in front of the iconic Sydney Harbour Bridge on May 10, 2013. (SAEED KHAN/AFP/Getty Images)