ETSU expert discusses solar eclipse, safety

Published 8:49 am Wednesday, April 3, 2024

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Still have those glasses from the last solar eclipse in 2017? Dig them out. 

A cosmic spectacle that will blot out the sun for more than 4,000 miles across North America is happening April 8.  

While much of the Appalachian Highlands won’t be in the path of totality – when the moon fully blocks the sun, resulting in complete darkness – viewers still need to take steps to prepare. 

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And that includes safety.  

“Everyone should absolutely heed the warnings to never look directly at the sun,” said Dr. Gary Henson, director of the East Tennessee State University Planetarium and a professor in the Department of Physics and Astronomy. “The same UV light that causes sunburn to your skin will damage the extremely sensitive retina of your eye in less than a second. In extreme cases, the damage can be permanent with serious vision problems.”  

The retina doesn’t have pain receptors, so spectators often don’t realize the damage is occurring. 

Henson recommends approved eclipse glasses or handheld solar filters. Those are the only ways to view the eclipse safely, he said.  

There are even options to make a device yourself.  

“It is also safe to view an image of the sun indirectly, and this is most commonly done with a pinhole projector, which can easily be made at home. Observers can find numerous examples of do-it-yourself versions of such a projector, which allows you to see a small image of the sun projected onto a screen or surface,” he said. “Remember: One does not look at the sun through the pinhole.” 

This is the second solar eclipse impacting the United States in seven years. But for much of the country, it will be the last one until 2044. 

You will still need to make a point to notice, even in Johnson City, where experts predict the moon will cover about 89% of the sun’s surface. 

“Although that may seem extreme, casual observers won’t even notice a change in the ambient daylight – assuming a clear sky that day – except for a time within about 10 minutes before and after the point of maximum coverage,” Henson said. “Even then, the effect will only be that of stepping into an area of midday shade.”