This Saturday, much of the continental United States will be treated to an astronomical event—an annular solar eclipse. In this type of eclipse, the apparent sizes of the moon and sun don’t align perfectly to Earth-bound viewers, resulting in a solar “ring of fire” shining around the edges of a moon nestled inside the boundaries of the sun.
The best viewing will come in a 125-mile-wide band known as the path of annularity, which will stretch from Eugene, Oregon to San Antonio, Texas, and then on into Mexico and Central America. Viewers outside that band will still be able to see some parts of the eclipse, with the percent coverage depending on how far they are from that central line.
Even though the sun will be partly covered, it is NOT safe to look directly at the sun without eclipse glasses. If you don’t have glasses, you can look at a projection of the sun through a pinhole onto the ground or another surface—but don’t look through the pinhole at the sun. Astronomer and author Dean Regas joins Ira for an eclipse preview, and to offer viewing tips on when, where, and how to best view the solar event.
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Dean Regas is outreach astronomer at the Cincinnati Observatory and co-host of the PBS program Star Gazers in Cincinnati, Ohio.
IRA FLATOW: For the rest of the hour, an astronomical highlight for your weekend– an annular solar eclipse that hopefully a lot of you might be able to see.
Joining me now to talk about it is Dean Regas, astronomer and author, based in Cincinnati, Ohio. Welcome back, Dean.
DEAN REGAS: Glad to be with you on Eclipse Eve here.
IRA FLATOW: Nice to have you. Tell us– what is an annular eclipse? And how is it different from a total eclipse?
DEAN REGAS: Yeah. So an annular solar eclipse happens when the moon is too far from the Earth so it doesn’t appear big enough to block out the entire sun. So I think a lot of people remember the total solar eclipse from 2017. This one is going to not quite block out the entire sun.
So if you’re in the right place at the right time, the moon seems to nestle right inside the sun’s disk, leaving this ring of fire around the moon. It is so cool.
IRA FLATOW: Is it safe to look at it, or do we still need those special glasses?
DEAN REGAS: It is absolutely not safe. I’m glad you said that. Because this is a partial solar eclipse, whenever any little bit of the sun is shining, you definitely need those glasses. So see if you can get some eclipse glasses.
Connect with your local astronomy club, science center, observatory, planetarium, they should be doing something. If you don’t already have the glasses, check with them. But yeah, don’t stare at this, please.
And you won’t really notice any difference in the brightness of the sky. So you wouldn’t even know this is happening unless you were ready for it and had those glasses.
IRA FLATOW: Is that right– because there is so much of the sun still coming through that ring of fire there?
DEAN REGAS: Absolutely. Even when there’s just a few percentage of the sun shining on you, it is still blazingly bright. So for people that are in the path of annularity– that’s this narrow swath of land between Oregon and Texas– it will dim a little bit around that time. You’ll see a little dimming. It’ll probably feel a little cooler outside. The light might be a little weird.
But I think the best thing is to actually watch the shadows, light coming through leaves and trees onto the ground, because it’ll cast little mini eclipses onto the ground that you can see.
IRA FLATOW: And what if we’ve lost our glasses for this eclipse, what are our options for viewing it?
DEAN REGAS: Yeah, that is tricky because I know a lot of people might have their glasses from 2017 and that eclipse.
IRA FLATOW: Right.
DEAN REGAS: You want to check those out to make sure they’re still safe. Shine a really bright flashlight through them. Make sure there’s no pinholes or distortions or anything like that. Just test those out.
But if you don’t have glasses, then you can do the pinhole method, where you let the light come through a hole in a piece of paper onto the ground and you look at the projection on the ground. You can do this with a colander, a trucker hat, Ritz crackers, anything with a little hole in it. And it’ll make little shapes and you’ll see the eclipsed sun on the ground. But just don’t look through the hole. Let the light come through the hole onto the ground.
IRA FLATOW: OK. Now, for the good stuff. Give us the ABCs of where you have to be living to see the annular eclipse.
DEAN REGAS: Well, a couple cool places that you can try to get to, if you could get there real fast. Crater Lake National Park, out in Oregon, is going to be a really nice place to go. But then the path will go from Oregon into Nevada, Utah. So Arches National Park is close to that.
Then down through New Mexico, where you can go to Albuquerque where the Balloon Fiesta is happening. And then Roswell, New Mexico, which is where I’m planning on viewing from, with all the aliens and whatnot. And then down through Texas and out.
So that’s this narrow band where you have to be to see the annularity. The closer you are to that band, the more of the sun will be blocked out. The farther away you are, then the less will be blocked out. So people in the Midwest will see about 50% of the sun blocked, and then people in the Northeast will see a little bit less than that.
IRA FLATOW: And what time should we be out there looking?
DEAN REGAS: Well, this varies. It varies greatly depending on where you are. So when the annularity begins in Oregon– it will be there first– so right around Crater Lake, annularity will be about 9:17 to 9:21.
Down here in New Mexico, it’ll be about 10:38 to 10:45. And if you’re in Texas, 11:52 to 11:56. But definitely check your local time because it will vary quite a bit.
IRA FLATOW: And as you said before, if you’re not right along the exact track of this eclipse, a lot of people will be able to see at least something, right?
DEAN REGAS: Yeah, that’s the thing about this eclipse is it’s visible almost over the entire United States. So everybody will see a little bit of something.
And I’m really trying to hype this one up because I think that maybe people have another date circled on their calendar for an astronomical event, April 8, 2024. That’s the date of the next total solar eclipse, which is by far the best, most amazing astronomical thing you’ll ever see.
And so this one is like the little rehearsal eclipse.
IRA FLATOW: It’s the warm-up– the warm-up act.
DEAN REGAS: It is the warm-up eclipse. This is the one where you can practice, make sure you have your safety equipment, practice that you can do some viewing safely. And even better than that, practice taking pictures. Because if you get some good pictures of this eclipse, you’ll be all ready for April. And man, I can’t wait for that one.
IRA FLATOW: Dean, it sounds like you’re excited. Thank you for cluing us in on it.
DEAN REGAS: Oh, my pleasure. Keep looking up.