Newswise — MANHATTAN, KANSAS — From coast to coast and across the heartland, the Aug. 21 total solar eclipse will be an awe-inspiring and rare event, says a Kansas State University physicist.
"This is our special Great American Eclipse and it's going to be a really remarkable event," said Chris Sorensen, Cortelyou-Rust university distinguished professor of physics. "If you have the ability to travel to the path of totality, I highly recommend that you go."
On Monday, Aug. 21, the moon will completely cover the sun in a total eclipse of the sun. A wide stretch of the United States — including northeast Kansas — is within the path of totality, which is a 70-mile wide path that goes from Oregon to South Carolina. It is the first total eclipse of the sun visible in the U.S. since 1979 and is the first total solar eclipse visible in Kansas in 99 years.
The only way to view the total solar eclipse is to be in the path of totality; anyone outside of the path of totality will only see a partial eclipse. Sorensen, an amateur astronomer, has studied the sky for years and offers tips to safely watch the Aug. 21 total solar eclipse, both inside and outside the path of totality.
What will happen
Around 11:40 a.m. in Kansas, the moon will make first contact with the sun and start the stages of partiality. A few moments before totality — which will be few minutes after 1 p.m. — people will be able to see Baily's beads, which are a series of bright spots of light from the sunlight passing close to the surface of the moon, skimming through lunar mountain valleys. Shortly after that, the diamond ring effect will occur with a single brilliant bead. Only when that last diamondlike bead disappears does totality start — and only then can people view the eclipse with the naked eye. Totality will last about two and a half minutes for people in the center of the path. The end of totality is marked by the reappearance of a diamondlike bead followed quickly by Baily's beads, which also marks the time that people should put solar glasses back on or use eye protection again. The moon makes its last contact with the sun around 2:30 p.m.
During a total solar eclipse, the environment changes, too, Sorensen said. Winds die down and temperatures get cooler. Birds start roosting and singing evening songs, crickets start chirping and nocturnal animals move as they would at night. An eerie darkness will descend.
"You want to make sure you watch the partial eclipse with your solar glasses on so that you can safety watch what is happening to the sun," Sorensen said. "Once the eclipse is total, take the glasses off. During totality, certainly look at the sun, which will be surrounded by its shimmering corona, but don't forget to take a look all around you to get a sense of what is happening to your environment, too. Remember, you're now in a 70-mile diameter dark shadow of the moon and that means all around you is sunlight. You may be able to see sunlight 30 or 40 miles in the distance, very likely with tinges of sunrise and sunset colors."
How to view the eclipse
It is never safe to look directly at the sun, Sorensen said, and all eclipse watchers should practice eye safety. Solar eclipse glasses and other protective measures should be used at all times for watchers outside the path of totality and during any partial phase. For watchers inside the path of totality, solar eclipse glasses and safety measures still should be used, but may be removed briefly during the moments of the total eclipse.
• Solar glasses and viewers
Make sure eclipse glasses or hand-held solar viewers are properly qualified for protecting eyes, Sorensen said. They should come from a reputable vendor and should include the certification that it meets the requirement for ISO 12312-2.
Only people in the path of totality can remove eye protection during the brief period of totality. The key is to watch for Baily's beads and the diamond ring: People can remove solar glasses and viewers when Baily's beads and the final diamond disappear before the total eclipse, but they must put eye protection back on when the beads reappear, marking the end of the total eclipse.
Sunglasses, photographic negatives, smoked glass and other dark objects are not safe ways to view the eclipse, Sorensen said.
"They may stop the visible light from the sun, but the ultraviolet and infrared light from the sun still comes through and those lights can burn your retina," Sorensen said. "Your retina, although sensitive to light, is not sensitive to pain. Your eyeballs could be burning and you wouldn't even know it."
The American Astronomical Society has more eye safety information at eclipse.aas.org/eye-safety/iso-certification.
• Telescopes
Telescopes focus light and make the sun even more intense to view, which means it is not safe to wear solar glasses and look into a telescope, Sorensen said. Rather, telescope viewers should place a reputable telescope solar filter over the aperture to make it safe to look at the sun through the telescope. People in the path of totality can remove the filter during totality and view the eclipse through the telescope, but Sorensen strongly recommends against this because one might mistime when the eclipse will end while still looking through the telescope.
If people don't have a filter, they still can use the telescope during the eclipse phases by adjusting the telescope focus and using a method called eye projection. With this method, people can use the eyepiece to project the sun's image on a piece of paper or other surface.
• Pinhole cameras
Pinhole cameras are a simple and effective way to view the eclipse, no matter if viewers are inside or outside the path of totality. To make a pinhole camera, take a pen and poke a hole in a piece of paper or cardboard and hold it in the sun during the eclipse. The sun will shine through the hole and project the eclipse stages as crescents on the ground a few feet away.
Sorensen also recommends looking underneath a tree during the eclipse because the overlapping leaves also act as pinhole cameras and the eclipse stages will be projected on the ground as a myriad of crescents.
Travel
For viewers traveling to the path of totality, Sorensen has a simple piece of advice: Leave early to allow plenty of extra travel time. The roads will be busy and possibly gridlocked as everyone travels to the path of totality. Plan ahead and have a backup plan.
Read more at http://www.k-state.edu/media/newsreleases/2017-08/eclipse81117.html
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