Vienna Connection

Some local science teachers went back to school recently for a lesson on the upcoming solar eclipse on Aug. 21 when a total solar eclipse cuts a path across the U.S. Instructors from Fairfax, Arlington, and other Northern Virginia counties attended a half-day workshop led by professor Harold Geller, Ph.D., of the Department of Physics and Astronomy at George Mason University.

During the event, which was sponsored by the Virginia Space Grant Consortium, teachers received ideas on teaching their students about the eclipse. “We tested the teachers’ knowledge,” said Geller. “They also worked in small groups to develop a lesson plan on the eclipse.”

Teachers also got a hands-on outdoor session on safe viewing of the sun and solar eclipse as well as a hands-on lesson on the moon’s phases. Geller said the lesson and safety precautions can be applicable to anyone with an interest in the event. “Everyone seems to know the date … but many are not aware of the times,” said Geller. “They vary by location. In Washington, D.C. on 21 August 2017 the partial solar eclipse will begin at 1:18 p.m. The peak or maximum will be at 2:43 p.m. The partial solar eclipse will end here at 4:02 p.m.”

For those who may be unaware of the specifics, Geller underscored the importance of understanding what a solar eclipse is. “Most simply, it’s the phenomena which occur when the moon gets in direct line of sight between the Earth and the sun,” he said. “In the D.C. metropolitan area, between 81 and 85 percent of the sun's disk will be blocked by the moon.”

For those in the Washington, D.C. region who are wondering what will be visible, Geller said, “At the start of the eclipse, it will appear that a dark disk is blocking out the light from the sun. As we proceed to maximum, more and more of the sun's disk will be blocked by the moon. Then, after the peak, less and less of the sun's disk will be blocked by the moon.”

For those wishing to see the eclipse without leaving the Washington, D.C. region, “The best place to view the eclipse is in the path of totality, that is, wherever the shadow of the moon will totally block all the light from the sun,” said Geller. “Another very important factor is the weather. You should have a direct line of sight to the sun, no interfering clouds. So an open field, with no interference along the line of sight to the sun between 1 and 4 p.m. in this area, would be best.”

Safety is a factor that Eric Bubar, Ph.D., associate professor of biology and physical sciences at Marymount University underscores.

“Never look directly at the sun, unless you can use approved solar viewing glasses,” he said. “These might be hard to find at the moment. Most online vendors are sold out.”

For those considering using their sunglasses instead of eclipse glasses, Bubar offers a warning. “Your sunglasses are not suitable for viewing the sun,” he said. “No matter how dark, expensive or polarized they are, don't use them. Polarization and UV blocking are great for decreasing the ambient brightness outside, but direct sunlight light can pierce right through and cause damage to your eyes. The only safe way to see the sun with your own eyes is through eclipse glasses or appropriate solar filters.”

“No one should ever look directly at the sun without proper protection,” added Geller. “Only special equipment should be used, whether looking directly at the sun or indirectly at the sun.

Only a limited number of manufacturers’ products have been tested for safety. Make sure you are using one of these or that you use an indirect method for observing the sun.”

Bubar recommends using the list of vendors certified by the American Astronomical Society. “Also, look at the glasses and make sure there are no holes or punctures in the viewing material,” he said. “Even a small crease or puncture can make them unsafe.”

Eclipse enthusiasts should not be fooled by glasses that appear similar to eclipse glasses that have been certified for safe viewing, says Bubar. “The material in solar filters can look a lot like aluminum foil but is completely different,” he said. “If you can't find solar viewing glasses … you can see it indirectly with a pinhole viewer.”

Instructions for using this method can be found by visiting: (https://eclipse.aas.org/eye-safety/projection) for how to do this.

For those wondering whether one can really go blind by looking at the sun: “Yes, you can,” said Bubar. “The sun is really bright. It sits 93 million miles from us, but the light it puts out is still great enough that it can cook your retinas and cause vision distortion or blindness even with only a small period of exposure.”