Countdown to the Great American Solar Eclipse: What time will it begin?

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By now, you have heard that The Great American Solar Eclipse will take place on Monday, August 21.

But do you know exactly when the event will begin?

The Answer Depends on Where You Live

Recall that what we experience on earth as the solar eclipse occurs because the moon passes between the earth and the sun; as a result, the moon's shadow is projected on to the surface of the earth.

Path of The Great American Eclipse (Courtesy: NASA)

Because the moon is constantly in orbit around the earth, it is constantly in motion; as a result, its shadow is in motion as well. This means that the eclipse is not a fixed or stationary event -- it will move across the earth at a steady rate (approximately 2,000 mph). According to NASA, it will only take 90 minutes for the moon's shadow to cross the nation, coast-to-coast, from Oregon to South Carolina!

As a result, the answer to "what time will the solar eclipse occur?" will change depending on the viewer's location. Below is a quick guideline for cities that are in the path of totality (100% obstruction of the moon compared to the sun).

Eclipse timing for various cities. Source: NASA

For a more detailed calculation (as well as the percent totality that the moon will block the sun), you can input your location into this calculator (click here to be directed to

Keep in mind that there are multiple "phases" to the eclipse, and the entire process takes about 3 hours.

With that said, you will notice the moon blocking about 50 percent of the sun roughly half an hour before "totality".

In Huntsville, the actual "totality" will only last for about 2 minutes, around 1:30pm. After 1:30pm, the moon will begin to move away from the sun, though the sun will remain partially block for another 90 minutes as the moon's shadow gradually gives way to full sun.

Eclipse Safety: Protect your eyes when looking up to the skies!

On a normal day, we normally do not look up and stare directly at the sun because our body produces ways for the situation to feel uncomfortable (ie, blinking, squinting, etc.)

For much of the Tennessee Valley (and specifically for Huntsville), as much as 97% of the sun's rays will be blocked by the moon. As a result, it will be very tempting to look up and watch the eclipse without eye protection, but doing so will cause permanent eye damage, including the potential for blindness.

Be sure to heed the safety information below, and keep in mind that your eyes may be injured if you view the eclipse through a camera, binoculars, etc, that have not been fitted with specific light-filtering lenses.

Refer to NASA's eclipse information sheet for recommendations on what to look for when obtaining proper solar eclipse eyewear. NASA also has a list of different retailers and sources for purchasing or obtaining the eclipse eyewear.

Solar eclipse eye safety (Source: NASA)

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