The Great American Eclipse: August 21, 2017
On August 21, 2017, millions of people across the United States will see nature’s most wondrous spectacle — a total eclipse of the Sun. It is a scene of unimaginable beauty; the Moon completely blocks the Sun, daytime becomes a deep twilight, and the Sun’s corona shimmers in the darkened sky. This is your guide to understand, prepare for, and view this beautiful celestial event.
Best Locations for Viewing?
The foremost criterion for selecting a site is the weather. Any location along the path of totality from Oregon to South Carolina can enjoy good weather on eclipse day, but the western half of the United States, especially from the Willamette Valley of Oregon to the Nebraska Sandhills, will enjoy the very best weather odds. You can watch the weather forecasts starting a week before eclipse day to judge whether you can strike for a spot close to home or drive further afield.
Wherever you go, every eclipse viewer should have a plan for mobility. Even in the sunniest locations, you don’t want to be caught under a cloud during the precious two minutes of totality. Pick a location with a good and uncrowded highway system that you can use to relocate the day before, the morning of, or the hour before the eclipse if weather threatens. The total solar eclipse will be such a spectacle that you won’t regret making the effort to find a clear viewing location. What causes a solar eclipse? The first fact to understand about solar eclipses is that they occur because of a remarkable cosmic coincidence: the Sun is just about the same apparent size in our sky as the Moon. While the Sun is actually about 400 times larger in diameter than the Moon, the Moon is also about 400 times closer than the Sun. Therefore, the Sun and the Moon appear to be about the same size in our sky.
This single fact explains why we see total solar eclipses – the Moon has an apparent size that just barely covers the Sun completely, yet is not too large that the Sun’s atmosphere, its corona, is eclipsed as well. We on Earth occupy a celestial sweet spot to witness this sight.
Eclipse Basics
What causes a solar eclipse? The first fact to understand about solar eclipses is that they occur because of a remarkable cosmic coincidence: the Sun is just about the same apparent size in our sky as the Moon. While the Sun is actually about 400 times larger in diameter than the Moon, the Moon is also about 400 times closer than the Sun. Therefore, the Sun and the Moon appear to be about the same size in our sky.
From begin to end, the eclipse lasts nearly three hours (including the partial stages) if you are within the narrow path of totality.
This single fact explains why we see total solar eclipses – the Moon has an apparent size that just barely covers the Sun completely, yet is not too large that the Sun’s atmosphere, its corona, is eclipsed as well. We on Earth occupy a celestial sweet spot to witness this sight.
There are two general rules for safely viewing solar eclipses:
- When any part of the Sun is visible, do not look at the Sun without approved solar filters that are used properly. Do not assume that sunglasses, exposed film, CDs, or any other ad hoc filter is safe. Only use approved solar filters such as eclipse glasses from a reputable source. Failure to heed this rule may result in permanent eye damage.
- During the two minutes of the total solar eclipse, it is indeed safe to look directly at the Sun’s corona with your eyes and through binoculars. But when totality ends and it suddenly brightens, instantly turn your eyes away and put your eclipse glasses or filters back on immediately.
Read more at www.greatamericaneclipse.com