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Pinhole projection method can be fun way to view eclipse

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Sunday, Aug. 20, 2017 4:34 PM

Greetings, stargazers.

I have never seen a total eclipse. However, I have seen many partial solar eclipses, including the annular eclipse that passed over the Four Corners in 2012. I find them all enjoyable, especially when I am in a position to share the experience.

Once the moon starts passing in front of the sun, it will take about an hour to reach maximum coverage. In Cortez, that coverage will be just over 80 percent at 11:40 a.m. The world will look darker than normal, but if you are not paying attention, it may not be noticeable.

You shouldn’t look directly at the sun because it is bright enough to damage your eyes. But this shouldn’t be much of a problem in Cortez because the sun will be so bright that it is hard to look at.

Dozens of low-cost, safe eclipse viewers are available online, such as those offered by Thousand Oaks. Homemade options exist, but the problem with these is that they might block enough visible light, but not block the infrared and ultraviolet light that can cause long-term damage to your eyes.

If you haven’t been able to obtain an eclipse viewer, the easiest way to observe the eclipse is with the pinhole projection method. Make a tiny hole in a piece of paper and hold it in the sunlight. The paper will make a shadow and the sun a small bright spot where the sun shines through the hole. During the eclipse, the bright spot becomes a little crescent shape on the ground. The farther away the hole is from the ground, the larger the image will be. I have heard of people using a cheese grater or something else with lots of little holes to make multiple eclipse images. One of my most memorable partial eclipses was when the trees filtered out most but not all direct sunlight. There were thousands of places that sunlight filtered through the leaves and therefore thousands of tiny crescents on the ground.

If you happen to make the trip to the path of totality, you should be in for a treat. There is a tremendous range of brightness within the visible corona, and fortunately, human eyes are particularly good at detecting such variations.

I am planning to make the drive to eastern Wyoming, where there will be some high-altitude balloon launches studying various effects of the eclipse.

Charles Hakes teaches in the physics and engineering department at Fort Lewis College and is the director of the Fort Lewis Observatory. Email him at hakes_c@fortlewis.edu.

Useful links

Eclipse Timetable in Durango: www.timeanddate.com/eclipse/in/usa/durango
Powerhouse Science Center: https://powsci.org
Astronomy picture of the day: http://apod.nasa.gov/apod/
An astronomer’s forecast for Durango: http://bit.ly/2eXWa64
Old Fort Lewis Observatory: www.fortlewis.edu/observatory
Four Corners Stargazers:
http://bit.ly/2eUqRJXhttp://bit.ly/2iGQPTbhttp://bit.ly/2igOSMc

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