August 21, 2017
1:21 PM CDT
A day millions of Americans will see the sight of a lifetime. A total solar eclipse will span the US from Oregon to South Carolina. Day turns to night for two minutes, and the moon will completely block the sun as the sun's corona is revealed.
What Causes a Solar Eclipse?
Solar eclipses occur because 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 our vantage point 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.
How Often Does a Total Solar Eclipse Happen?
The last time a total solar eclipse was visible from coast to coast was in June 8, 1918.
What To Bring
Eclipse Viewing Glasses
NOT to look at the sun with! But to cut down glare when you're looking at everything else.
Sunscreen Small Tables/Chairs
White Towels Extra Batteries
Hat Cell Phone Charger
Blanket Duct Tape
Electrical Tape Water
Traffic- Please remember that there will potentially be more people in a given area than normal and that traffic may be backed up at unusual times. Some towns may have safety officers in place to direct traffic or even to stop traffic during the 2+ minutes of totality.
Safety Glasses- In order to safely watch the partial phases of the solar eclipse, you must have ISO-certified eclipse viewing glasses. It is best to get them before eclipse day to avoid the inevitable shortages. Your eyes will not be protected by a telescope, binoculars, camera lens or cell phone camera, either. Never look directly at the sun through any of these devices.
Observing the Sun can be dangerous if you do not take the proper precautions. The solar radiation that reaches the surface of Earth is from ultraviolet (UV) radiation. The tissues in the eye transmit a substantial part of the radiation between 380 and 1400 nm to the light-sensitive retina at the back of the eye. While environmental exposure to UV radiation is known to contribute to the accelerated aging of the outer layers of the eye and the development of cataracts, the concern over improper viewing of the Sun during an eclipse is for the development of "eclipse blindness" or retinal burns.