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Posted on 06-30-2017

Safely Viewing the Solar Eclipse:

On August 21, Americans will have a rare opportunity to view a total solar eclipse. The last similar eclipse was in 1918. A solar eclipse occurs when the orbits of the moon and the sun align in a way that the moon fully blocks the sun resulting in a short period of total darkness.

Solar eclipse in Spartanburg on August 21st, 2017

Viewers of the solar eclipse need to take proper precautions to protect their eyes. Directly staring at the sun at any time without taking precautions can be dangerous. The sun is not any stronger than normal during an eclipse, but where you would squint, blink and turn away from the full sun on a normal day to protect your eyes, it can be more comfortable to look at the sun during an eclipse because the sun blocked partially by the moon does not seem as strong.

Staring at the sun for even a short time without wearing the proper eye protection can damage your retina permanently. Exposure of the retina to intense visible light causes damage to its light-sensitive cells. The light triggers reactions within the cells which damage their ability to respond to visual stimuli. The result is a loss of function of these cells which may be either temporary or permanent, depending on the severity of the damage. Essentially the sun's rays are burning these cells. The damage can cause permanent blind spots in one's field of vision.  Unlike our skin which has pain receptors which alert us to a sun burn, there are no pain receptors in the retina. Damage to the retina is a painless event. Side effects from the damage are often not immediate. 

The best way to view the eclipse during the partial phase is by wearing a pair of approved eclipse sunglasses. Ordinary sunglasses do not offer enough protection. Whereas ordinary sun glasses transmit 10 to 20 percent of the light, eclipse glasses only transmit 0.0001 percent of the light.

The only time that the Sun can be viewed safely with the naked eye is during a total eclipse, when the moon completely covers the disk of the sun. In fact, if you don't remove your glasses during the period of the total eclipse, you will not see anything. There will be total darkness. It is never safe to look at a partial phase of an eclipse without proper measures.

If you do not have access to eclipse glasses, the eclipse can be experienced by creating a simple card projector.

Simple Card Projector

You Need:

  • 2 sheets of plain white paper (pieces of stiff white cardboard such as paper plates may work best) 
  • a thumbtack, a sharp pin, or a needle

What to Do:

  1. Take one sheet of paper and make a tiny hole in the middle of it using the pin or thumbtack. Make sure that the hole is round and smooth. With your back towards the Sun, hold 1 piece of paper above your shoulder allowing the Sun to shine on the paper. 
  2. The second sheet of paper will act as a screen. Hold it at a distance, and you will see an inverted image of the Sun projected on the paper screen through the pinhole.
  3. To make the image of the Sun larger, hold the screen paper further away from the paper with the pinhole.

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