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Astronomers discuss do’s and don’ts for viewing Aug. 21 ‘Great American Eclipse’

Wednesday, July 26, 2017

LAWRENCE — On Aug. 21, a total solar eclipse will cut across the U.S. in a diagonal track running from Oregon southeast to South Carolina. The once-in-a-lifetime astronomical event will be partially observable (with 99.3 percent coverage) on the main campus of the University of Kansas in Lawrence at 1:07 p.m., with the path of totality taking place roughly an hour’s drive to the north.

Barbara Anthony-Twarog and Bruce Twarog, both professors in the KU Department of Physics & Astronomy, will be present at Shenk Sports Complex at 23rd and Iowa streets in Lawrence for the public Eclipse at KU event from 11:30 a.m. to 1:30 p.m.

For those attending Eclipse at KU, those watching from home or those brave souls venturing to the path of totality, Anthony-Twarog and Twarog offer guidance to best view the once-in-a-lifetime astronomical event.

Q: What’s going to happen during the eclipse on Aug. 21, and why is it significant or worth viewing?

Barbara Anthony-Twarog: This type of eclipse — a total solar eclipse — is very rare, and it can be really spectacular. The moon is passing directly in front of the sun, and the lineup is so nice in all dimensions in space that at some locations in the U.S. the sun will be completely blocked out. If people are in the path of totality, for a couple of minutes they may see parts of sun we can’t usually see — like the corona, which is dim, and the reddish chromosphere.

Q: We keep seeing these cheap glasses that look like old 3-D movie glasses. What do they do, and do they really protect your eyes? Is there other eyewear a person could use to get a better view?

Bruce Twarog: Those are by far the best thing because you know in advance that they are designed for the purpose. Some people want to use welders glass or smoked glass, but they aren’t made for viewing the sun, so you don’t know if those will work, so we really recommend getting eclipse glasses.

Barbara Anthony-Twarog: We will have them at the events here at KU. The KU administration is buying a bunch to distribute at various Hawk Week events. There are a lot floating around. We’ve also brought and provided enough to Lawrence Public Schools so they can give them to students.

Q: Are there advantages to using a telescope equipped with a sun filter to view the eclipse?  

Bruce Twarog: The answer probably is no given the size of the sun in the sky. Do I want to look at the moon with a telescope — yes, because you can see craters and features. But with the sun you’ll just see a ring of light that’s blocked by the moon. You’re just as advantaged by looking with the naked eye as you are with a telescope. We’ll only have six telescopes set up at this event, and having people standing in line to use a telescope during the eclipse doesn’t make sense.

Q: Some areas like here in Lawrence will have a partial eclipse while other areas will have a total eclipse. What is the nature of that difference from the perspective on the ground, and is it worth traveling to the path of totally — for those on the fence?

Barbara Anthony-Twarog: If you’re on the fence, you should think carefully about capacity in locations you’re hearing about. There are many people going to St. Joseph (Missouri) with reservations to park their cars. There are estimates of hundreds of thousands of people trying to get to St. Joseph and Atchison. If you have plans to safely get to the path of totality, it might be worth the effort — but it’s not something to be taken lightly.

Bruce Twarog: For people who are able to park their cars, if you’re in the zone where it’s a total eclipse you can take off your glasses for 2 minutes of totality and observe. Here in Lawrence, you can’t do that — even with 99.3 percent coverage. The 0.7 percent of the sun that’s not blocked is still enough to damage your eyes, so you’ll always be restricted to using glasses.

Q: What will an astronomer be looking for that an average person might not be aware of? How can regular people look at the eclipse more like a scientist?

Barbara Anthony-Twarog: I think everybody is in the amateur group in the sense of appreciating and enjoying this. We don’t depend on eclipses anymore to get data on the sun. That was true hundreds of years ago. There’s no particular scientific value to watching the eclipse. I think everybody should kick back and enjoy it.

Bruce Twarog: There hasn’t been scientific value for eclipses since space missions got us beyond the atmosphere and allowed us to observe the sun anytime we wanted to.

Q: What if it’s cloudy?

Barbara Anthony-Twarog: We won’t be seeing very much! There’s probably a 30-40 percent chance of cloud coverage on average in August around here. We can’t do anything about it. But it will get dark. It’ll be very confusing for wildlife.

Bruce Twarog: It would be a lot like dusk here in Lawrence. In the path of totally, it would be totally dark, as if it were at night.

Q: At night, you need to get away from light pollution to see the night sky. Is there any similar concern for a daytime eclipse — places to avoid or seek out for optimal viewing?

Barbara Anthony-Twarog: I don’t think so. The daylight sky brightness is so overwhelmingly bright, and here you’ve knocked out 99 percent of it. The real question is if we’ll be able to see stars or a couple of bright planets. I don’t think it’ll make any difference going anywhere special.

Bruce Twarog: If you can see the sun, you got it — that’s all there is to it. If you can see the sun, you’re home free.

Q: How soon beforehand and how long afterward will the sky be worth paying attention to?

Barbara Anthony-Twarog: The actual event spans three hours. So, if people use imaging devices or special protection they should be able to start seeing the moon’s disc nick into the sun around 11:40 a.m. here. Then the maximum here is at about 1:07 p.m. And then the sun’s disc will come out from behind the moon and it’ll all be over by 2:40 p.m.

Q: Are there interesting stages? What are Baily’s Beads, and the Diamond Ring, for example?

Barbara Anthony-Twarog: Those are phenomena you can see if you’re in the path of totality. Bailey’s Beads refers to light coming around to see geographical features of the moon — so it will be brighter in some spots than others. The ring refers to the last bright spot of the photosphere visible before totality. But we won’t see those features in Lawrence.

Q: Can parents use the eclipse to teach their kids about astronomy? What are the points to emphasize behind the science?

Barbara Anthony-Twarog: We always hope so. People really are taken with these kinds of phenomena — so it’s an opportunity to go over a basic understanding of the sun, moon and Earth and cycle of phases throughout the year. It’s a part of our lives, and this is an opportunity to walk kids through that.

Q: What are the best resources to understand the astronomical science behind the eclipse? Are there books, websites or podcasts one could consume to bone up on eclipse knowledge?

Barbara Anthony-Twarog: We have a website. We have a number of resources on the eclipse —  like how to make a pinhole camera. NASA is dominating the public education and outreach for this event. They have a number of fantastic videos, and I’m sure there will be a live feed of the eclipse, but those websites might be overwhelmed.

Q: How excited are you about the eclipse? What does it mean to you? How rare is this, anyway?

Bruce Twarog: There was a partial one in the early 1990s, but it was nowhere near total. If you’re in the path, this is the one time in your life to see it. 

Barbara Anthony-Twarog: At any particular place on Earth, it’s three or four centuries between a total eclipse on average. When was the last time Lawrence or Kansas City has had a total eclipse? The answer is never. So, yes — we’re really excited! 

Image: The Aug. 21 eclipse’s path of totality cuts through Northeast Kansas and Missouri. Image courtesy of NASA.