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On August 21, 2017, residents of the continental United States are in for a treat.
A total solar eclipse will sweep across the country, the first to be visible from the
lower forty-eight states since 1979, 38 years ago.
The path of the eclipse is predicted to travel from Salem, Oregon to Charleston, South Carolina,
and pass over many large cities and populated areas - making this eclipse potentially the
most-viewed total eclipse in the history of the world.
So, what is a total eclipse?
A solar eclipse occurs when the moon gets between the sun and the earth and blocks the
sun's light from hitting the earth's surface.
Many times, the moon only blocks part of the sun's light, resulting in either a partial
eclipse, or an annular eclipse.
During a total eclipse, the sun and the moon line up perfectly, and to people within a
small area, the moon seems to completely cover the sun.
Inside the moon's shadow, it will become very dark, like it is night.
Stars will be visible.
The temperature will drop.
You might even hear nocturnal animals begin to call!
A total eclipse happens somewhere on earth about every year and a half, but it is much
less common for them to be visible from where people live.
For example, many, many eclipses occur over the ocean, and still others happen over uninhabited
land.
For most people, being within range of a total eclipse is a once-in-a-lifetime event!
If you will be in the continental United States on August 21, 2017, and want to see the eclipse,
carefully check the maps provided by NASA to see how far you are from the path of totality.
If you are nearby, you may wish to travel to a location where you can see the total
eclipse.
It's a good idea to make plans ahead of time and carefully select a place to watch the
eclipse.
Remember, thousands of other people will also be traveling to view this rare astronomical
event.
If the path of the eclipse is too far from you, don't worry!
Most of North America will still be able to view it as a partial eclipse.
It is very, very important to consider safety when preparing to view the solar eclipse.
Looking directly at the sun is dangerous and can cause eye damage or even blindness, and
this is still true during an eclipse.
The exception is during totality, or when the disk of the sun is completely blocked
from view by the moon, when it is safe to look directly at the sun.
However, totality will only last at a MAXIMUM for two minutes and forty seconds, so it is
important to prepare to observe the eclipse in other ways.
There is only one way to safely look directly at the sun when it is partially eclipsed,
and that is through a special solar filter.
Solar filters can be handheld or in the form of 'eclipse glasses.'
Be sure whatever filter you select is ISO certified, and check to make sure they are
not scratched or damaged before use.
Except during totality, do not look at the sun through a camera, binoculars, or a telescope,
even if you are using a solar filter.
These devices concentrate the sun's rays and can seriously damage your filter and your
eyes.
For those without solar filters, there are simple indirect viewing methods you can use
to track the progress of the eclipse towards totality.
The first is simple: look for a leafy tree that casts a shadow on a smooth surface.
The tiny gaps between the leaves will project the image of the eclipsed sun.
If there are no convenient trees nearby, you can criss-cross your fingers to get the same
effect.
Finally, you can make a pinhole projector to cast a single, clear projection of the
sun.
Take a piece of card and poke a small round hole into it.
Hold it between the sun and a smooth, solid surface to see the progress of the moon across
the sun.
Viewing a total eclipse is a once-in-a-lifetime event for many people, so it makes sense to
be prepared!
Don't forget to check the maps for the time and location the eclipse will occur nearest
you.
If you wish to view the eclipse directly, be sure to purchase a certified solar filter
to protect your eyes.
Finally, indirect viewing of an eclipse can be fun and exciting, even for observers outside
the path of totality.
Are you prepared for the Great American Eclipse?
Good luck in your viewing, and goodbye till next time!