This is a special recording of Astronomy Cast to prepare for the Eclipse, recorded live in St. Louis, MO at the Astronomy Cast Solar Eclipse Escape 2017. We’re going to give you a set of last minute tips and info to prepare for the Great American Eclipse!
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What are eclipses?
Sharing eclipses with kids & how to make a pinhole viewer
Eclipse viewing guidelines
Diamond Ring Effect
Citizen CATE Project
Super cool interactive map
NASA Eclipse Page
NASA Eclipse Map
Interactive Eclipse Map
Night? Sky Network
Transcription services provided by: GMR Transcription
Fraser: Astronomy Cast Special Episode: Solar Eclipse 101.
Hello, everyone. I’m Fraser Cain, publisher of Universe Today. This is Dr. Pamela Gay. I don’t remember your title because it’s so new.
Pamela: It’s alright. I am the Director of Technology and Citizen Science at the Astronomical Society of the Pacific.
Fraser: And the Director of CosmoQuest. Hey, Pamela. How’s it going?
Pamela: It’s going well. How’s it going, Fraser?
Fraser: Good. So, for those of you who are listening to this, in the feed we are live, in person, with more than 100 of our closest friends here in St. Louis, Missouri in preparation to go and watch the solar eclipse that happens in two days.
Pamela: Two days. This is one of those things where people have been planning for this their entire lives because this is not an eclipse of the century. This is an eclipse of once in a nation. The last time there was a solar eclipse that transversed this much of the current United States, our country wasn’t here.
Fraser: And the fact that it’s doing it in the middle of summer when we stand a chance at getting good, clear skies across the country – yeah, this is unbelievable. I checked, actually. The one that’s in 2024 happens in April.
So, this is it. This is the one. This is our chance. So, here’s for some clear skies. So, we’re going to just give you some tips, tricks, last minute to-dos, don’t do’s, safety precautions and give you an idea of what it is that you’re going to see. So, where shall we start? Pamela, what is an eclipse?
Pamela: An eclipse, you have two different options.
Fraser: Just solar eclipse.
Pamela: Okay, just solar eclipse. Fine, fine. You’ve removed the punchline from my story. So, a solar eclipse is where we have a line-up of the earth, then the moon, then the sun and the sun is really big, but it’s far, far away and because it’s far, far away, it appears to be on the sky the exact same size as our tiny little – but fairly nearby – moon. This is a fairly unique alignment. We do have other moons that transverse in front of the sun compared to their planet, but they’re tiny and they don’t block out the whole sun.
So, it’s sad and boring. But with our moon, we get this amazing opportunity. So, when we’re all little kids, we draw the sun with all of these little rays coming off of it. Those are actually there and during totality, we get to see them. That’s the sun’s corona. So, it goes earth, moon, sun. The main body of the sun blocked out, corona not blocked out, we get to see the corona.
Fraser: Right, and I know for a lot of the population, they get to see when the lunar eclipse is because really if you can see the moon, you can see the lunar eclipse when it’s happening. But for the solar eclipse, it’s a very specific part of planet earth that gets a chance to see it. So, who is gonna get a chance to see the eclipse?
Pamela: So, this time the shadow of the moon touches the earth and moves across a line that goes from off the coast of Oregon across Oregon, Idaho, Missouri – I’m sure I’m missing some states in there. Wyoming is in there. I missed Wyoming. Wyoming and then it comes across we have Idaho, Missouri, Illinois. Keeps going, starts hitting the southern states.
It goes through Nashville, Tennessee, hits a tiny little bit of Georgia, hits a whole lot of South Carolina. It’s estimated that there will be many million people – possibly as many as 100 million people – who fill this 80 mile wide stripe across the country, which gets us to the problems that are going to occur on Monday.
Fraser: Right, I mean because to really appreciate the most totality you can possibly get, you want to be right in the middle of that eclipse path. That lets you see the most. If you’re on either side of it, then you see less totality and then if you’re outside of that actual shadow path, then you’re going to see a partial eclipse – which I’ve heard sucks, right? Like if you’re listening to this and you’re like, “Oh, that’s okay. I’ll see a partial eclipse.” I’m sorry to tell you it’s apparently not the same thing. It is I’ve heard described the difference between seeing a lightning bug and seeing lightning.
Fraser: Yeah, that moment that when you actually see the moon cover the sun completely and all of the weird things that happen, at that moment it is – yeah, and it is a bucket list for everyone. So, again, I apologize if you’re not able to make it down or if you live in a part of the world that’s not gonna see it, I’m so sorry. It can happen again.
Pamela: So, I personally have only ever seen partial eclipses. I’ve tried to see totality twice. I was rained on both times. I’m abandoning your sorry asses on Monday. I am abandoning you. So, hopefully because I’m spending the entire day working, I will not bring my bad mojo to this group.
Fraser: Does that mean you’re gonna go and take rain far away from us to the rest of us can appreciate it?
Pamela: No. I’m just working, so I won’t be enjoying it and – as long as I’m not trying to enjoy and eclipse – I figure maybe the universe will be kinder.
Fraser: But with this, I mean I’ve been trying not to check the weather because it’s like, “It’s done. We came to St. Louis. We’ve got buses. We know where we’re going. This is happening and we can’t make the sun and the moon stop. So, we’re gonna get a chance to see it.” So, for those of you who heeded our wise advice like literally a year ago and they have made their way down and they’ve made arrangements and they’re gonna be under the eclipse path, what will people see?
Pamela: So, the first thing that they’re going to see is a massive amount of traffic. So, as someone who lives a couple miles from totality, we have been warned that they are going to be treating this like a massive weather event. They are bringing out the National Guard. They are expecting traffic to end all traffic. So, when I say the first thing you will see is traffic, I mean that may be all you see.
Pamela: So, if you still have time, leave now.
Fraser: Yeah, or but even like if you were within striking distance of the eclipse and you want to get onto that totality path–
Pamela: Leave now.
Fraser: It’s not crazy to leave the night before or like midway the day before, right?
Fraser: It could get pretty snarled. So, I think for us, we’re gonna leave at 5:00 in the morning?
Fraser: 5:30 in the morning. By the way, I don’t know if you’re all aware of this. We’re gonna go at 5:30 in the morning.
Audience: What time zone?
Fraser: This one. But yeah, so leave early and so traffic okay. Great. You’re gonna see the great traffic eclipse.
Pamela: So, beyond seeing lots of traffic, leave early, leave the night before. Take enough water for two days. Beyond seeing vast amounts of traffic, what you will see is when the moon is completely in front of the sun. You’re like in a really deep shadow. So, it will appear like after twilight when you’ve hit the point the sun is completely below the horizon, but you can still look around and see stuff and the animals are going to behave accordingly.
So, even though at most you’re looking at almost three minutes of totality in this part of the country, the animals are like, “I don’t know it’s only gonna be three minutes long. I don’t even have a wrist. I’m not wearing a watch.” So, they’re gonna perhaps behave strangely and there’s actually a bunch of biologists who are asking you if you see this to take a recording.
Fraser: But there’s gonna be things that will happen before it’s complete darkness, right?
Pamela: Well, the animals will start being confused.
Fraser: Yeah, but the fact is like those of us – like the totality you said that’s three minutes where we are, but we’re gonna see partial eclipses for a couple of hours.
Pamela: Of hours.
Fraser: Yeah, beforehand.
Pamela: So, this is beautifully timed for us here in the middle of the country. This is a lunchtime event. So, grab yourselves what I’m recommending is grab yourselves your lunch early, find someplace to sit, and just blindly eat while wearing your eclipse glasses. Do not look directly at the sun and practice with your eclipse glasses ahead of time so that you know how to find the sun without taking them off, looking at the sun, seeing red spots, and not being able to see anything when you put your eclipse glasses back on – so, practice.
Pamela: And while you’re looking at these partial phases, essentially the sun is slowly going to become a very rounded out PacMan. So, if PacMan had been done when they had better vector graphics and had a more realistic mouth, that is what the sun is going to slowly look more and more like as we edge towards totality. It won’t get noticeably darker initially, but the shadows are gonna get really weird. So, where sunlight passes through trees, normally you have nice, round suns of light passing through the trees.
But, in this case, you end up with crescents of sunlight going through the trees and this just will look creepy. One of the things that you can actually do is build a pinhole viewer. Emily Lakdawalla on The Planetary Society blog has really awesome directions in many languages on how to do this and you can, for instance, make your favorite Pokémon character and a bunch of pinholes, project the sun through it, and get all of these little crescents outlining your Pokémon character or your Snoopy or your smiley face.
Fraser: There are some great pictures I’ve seen where someone like there’s a tree and there’s shadows from the leaves of the tree and you can see hundreds of little eclipses on the ground, which is really, really neat. So, look for these kinds of almost natural pinhole cameras around you to cause these really fascinating shadows. So, over the course of this like how long does the partial phase part last?
Pamela: It’s about two hours on both sides.
Fraser: Okay, so about two hours. So, you’re gonna have a lot of time while we’re stuck in traffic to watch the partial phase happen. But then as it gets closer and closer to totality, that’s when things get pretty exciting.
Pamela: And as we get towards totality, the sky is going to get darker and darker and darker and one of the nifty things that happens is you suddenly start being able to see planets. The star Regulus is gonna be snuggled up right next to the sun. It may become visible. So, open up Stellarium. Figure out where these different things are going to be relative to your horizon and, if you happen to be in Carbondale, we actually have a finding map on the back of a t-shirt that is available at AstroGear.spreadshirt.com and you can get a finding chart on a t-shirt.
Fraser: Right. So, everyone’s got their finding charts – these blue shirts that some of the people are wearing – on the back there is a map of the planets and the bright stars that you’re gonna be seeing. But, you’re gonna be able to see Mercury and Venus and Jupiter and Mars?
Pamela: The star Sirius.
Fraser: And Mars I think and yeah and Sirius. But for those of us who have never seen Mercury – because I have mountains to the west and to the east of me so I never see Mercury – and so this will be like one of the first and only times I’ll be able to actually see Mercury is because the moon will have destroyed the sun. But finally, it’s all I could have hoped for. Okay, so now as the sky is getting darker, the sun is almost entirely eclipsed. What’s gonna happen next?
Pamela: So, in the seconds before the total eclipse there’s gonna be these weird snake-like shadows that may be seen. These aren’t fully understood. It may be some sort of an interference effect that’s happening. But one of the things that has been previously observed – Google videos on this – is basically shadow snakes. It’s you get these rippling – to me they look like interference lines – but again we haven’t fully figured out what the heck is going on.
Fraser: We’re gonna see these on the ground?
Pamela: Yeah, up the sides of buildings. It’s this very brief period where you get essentially light and dark playing with one another that looks like wiggling snakes of light.
Fraser: And then you’re going to see the little spots of sunlight?
Pamela: So, these are Baily’s Beads or the Diamond Ring effect. Along the edge of the moon, you have mountains and valleys and craters and pits and the sunlight can get blocked by everything except for where it sneaks through the valleys and the spaces between the mountains. So, where it sneaks through, you get these beads of light that these are actually my favorite part because they’re just so pretty.
Fraser: That’s mind bending through, right? You’ve got the moon – which looks like just this perfect circle in the sky, the same with the sun – but that because the shapes come together so nicely, you’re gonna be able to see the sunlight coming through those little mountain valleys on the moon with your own eyeballs, which is just –
Pamela: And what’s cool is you can actually do science with this. So, there’s a project called the Mega Movie. The free glasses that are being given out at libraries and schools and we have them here at our Astronomy Cast event. All over the United States, the Astronomical Society of the Pacific, the University of California at Berkley and a bunch of other organizations have been working with Google to put together this project where we’re collecting photos from any of you all that have DSLR cameras that can take photos.
Submit them in, submit where you were when you took the photos, when you were when you took the photos, and we’re each going to have our own personal, unique alignment between our camera, the moon, and the sun that can get used to map out the finest features along the edge of the moon. So, this is science you can contribute to through the Mega Movie Project and there’s also an app. So, download the app.
Fraser: Yeah, yeah. To do research for Mega Movie and you’ve still got time and literally thousands of people along the eclipse path are going to create this incredibly precise image of the moon that scientists are going to be using. So, then that’ll be the last time that we’re gonna see the sun forever, right?
Fraser: So, now the sun has been destroyed. What will we see in the sky now?
Pamela: So, when the great dragon in the sky is done consuming the snake, we should all bang our pots to scare the dragon away.
Fraser: Okay, alright.
Pamela: This has been proven to work. The sun keeps coming back from these events, but–
Fraser: Has anybody tried not banging the pot and see what happens?
Pamela: There’s always one person banging the pot.
Fraser: As long as somebody does, then the sun will return? Okay.
Pamela: That one person banging the pot will save us all.
Fraser: Yeah. So, we’re gonna see the corona?
Pamela: We will see the corona. So, the solar corona is this super-hot gas that again every year or two we end up with a new scientific explanation on why we think maybe the corona is so darn hot. So, it’s complex. It’s hard to understand. It behaves in mysterious ways and one of the frustrations that we scientists have is we can see the disk of the sun. We have that technology.
We have spacecraft and coronagraphs here on the surface of the planet that block out the disk of the sun and let us see the outer corona – but the part of the corona that’s snuggled up right next to the sun – it always gets blocked out so that we don’t accidentally damage our cameras. We don’t accidentally damage our spacecraft. So, we never get to study this and so Project CATE – which is another NASA project – they have almost 70 groups with identical telescopes, identical cameras spread out across the entire path of totality.
They’re going to be constructing a more than 90 minute long movie of how that corona is moving and changing and interacting as the eclipse shadow moves across the United States and – as long as we don’t end up with any big areas of clouds or smoke which we’re looking at having in Oregon – they will be able to do an unprecedented study of how the inner corona works and maybe we’ll get a little closer to figuring out why the heck there’s all this hot gas that’s hotter than the surface of the sun next to the surface of the sun.
Fraser: But what will it look like?
Pamela: It will look like all those squiggly drawings that we did as small children.
Fraser: Okay. I’m thinking like some kind of ghostly streamers and like around the sun.
Fraser: How much – compared to the size of the sun – how big will the corona be?
Pamela: So, I’ve never seen it with my eyes because I get rained on. So, the more you’ll be able to see is related to how good the atmosphere and how active the sun is that day. So, if there’s a coronal mass ejection that goes off at just the right moment, there might be this giant fiery blob coming off the sun at the side of the sun that might destroy satellites later.
Fraser: That’d be great.
Pamela: But if we’re seeing it, it’s not pointed at the earth. But if there’s one pointed at us, we won’t see it because there’s an eclipse and that would be bad. But this is why there’s people outside of totality. They will warn us of our impending doom as the sun destroys us.
Fraser: Now you’re gonna scare people. It’ll be like make the northern lights look really pretty for a couple of days. Okay. So, we’re seeing the corona. How long have we got for totality?
Pamela: It depends on where you are. If you’re right on the edge of totality, it’s like less than a second if you’re standing on the edge. The closer you get to that 70 to 80 mile wide eclipse band – the closer to the center you get – the longer the duration. So, in this part of the country we’re looking at almost three minutes of totality and where we are in Carbondale, that’s what we’re gonna get is pretty much maximum totality. Now, as you get further and further from the center of the center line, you get less and less eclipse.
Fraser: Right, and then the three minutes are just shy of three minutes will wrap up and then the little dots of fire will appear again – but now on the other side of the moon – and you’ll know that’s when it’s time to put your glasses back on.
Pamela: And they’re not actually fire. They’re called Baily’s Beads. They’re just happy, little sparkly bits of sunlight poking through valleys.
Fraser: Yeah, I didn’t say it was actually fire.
Pamela: I’m just making sure.
Fraser: Yeah, yeah. Yeah, and so then you’re gonna see the Baily’s Beads appear on the other side of the sun and then it’s all going to go in reverse. So, then you’re gonna get a chance to see a parking lot’s worth of car traffic, but now slowly brighten as the sun returns. It’s very important. We’d be remiss if we didn’t talk about safety. So, let’s talk about safety for the next hour. I’m serious. Every time I talk about the eclipse everyone is like, “Yeah, but you didn’t cover the safety part enough.” So, let’s sure that we absolutely, deeply cover the safety part so nobody has any illusions that we haven’t made sure that everybody’s eyes are perfectly safe.
Pamela: So, first of all, if you bought brand new glasses this year, flip them over. Look to see if they have the ISO code on it and make sure that they’re made by a reputable manufacturer. There have been evildoers taking advantage of people via Amazon who put the safety coding on the back and lied and if you use those glasses the entire time, you will burn your eyeballs out. Your eyeballs will probably start to hurt. If your eyeballs start to hurt, yeah stop. So, rule one, if your eyeballs hurt, stop.
Fraser: Yeah, but you want to see that ISO certification, ISO-1 – I forget the number – one, two, three, two, three dash one or something like that?
Pamela: The safety information – and you can check all of this – is at Eclipse.aas.org. So, check it out there. You can learn everything you need to know about verifying that you have safe glasses there.
Fraser: Yeah, and normally when you go and look at the sun, the sun is bright and you’re like, “Oh, I can’t look at the sun.” That’s your natural safety mechanism kicking in to keep your eyes safe. But as we get less and less sun, it’s gonna be easier for you to look in the direction of the sun and more and more tempting to do that. So, definitely make sure that you’ve got your certified eclipse glasses. Now when can you look at it with the unaided eye? For how long?
Pamela: Only during totality.
Pamela: So, if you are not with a large group of people – some place where they likely have shout-y machines that will shout “Totality. Take your glasses off.” There is actually an app that will shout at you. So, get the app that will shout at you and tell you when totality is happening and that is when it is safe to take your glasses off.
Fraser: Yeah, and that’ll be when – but pretty much like when you see the Bailey’s Beads is that the beginning of totality or just–
Pamela: When the Baily’s Beads go away, that’s the beginning of totality.
Fraser: Right. So, keep your glasses on until you see the beads and then when they go, then you’ll be in totality and you won’t have to have them on. and when you see the beads start to appear, get the glasses back on.
Pamela: And this is where I want to reiterate – practice, practice, practice. We have a couple of days and you can go outside and just get accustomed to putting your glasses on and then – with the glasses on – steer your face until it is maximally hot and you should be looking at the sun. Now the reason that you want to practice this is because otherwise what you’re going to do is what I inevitably do the first time I practice each season, which is look at the sun, put the glasses on, and only see red after spots.
Fraser: Yeah, and this is really important because when totality happens, it’s gonna be dark and the faint features that you’re gonna be seeing of the corona and such are gonna require you to have fairly dark adapted eyeballs. So, if you have gone and looked at the sun and closed down your pupils because you’re now adapted for bright lights, when you then want to – You’ve only got three minutes. It’s gonna take you longer for three minutes for your eyes to dark adjust to be able to see these really faint features in this ghostly corona.
So, you want to protect the dark vision side of your eyeballs as much as you can. So, really you want to keep those glasses on right as best you can to kind of keep your eyes in a more darker place so that when you do then take them off to see these fainter features, you’re not gonna have this big fault sun in your eyes because you’ve burned them out for the next ten minutes and you’ll miss that totality. So, it’s really important to protect your eyes and – as Pamela says – really practice. Make sure you’ve got that movement practiced a couple of times so that when it actually happens, you know what you’re doing.
Pamela: And with little kids, little kids aren’t gonna be able to sort this and by little I mean I wouldn’t really trust any little kid under about age seven to figure out the whole eclipse glass where’s the sun kind of thing. For them, you really just want to use a pinhole viewer. Again, Emily Lakdawalla has amazing instructions on her Planetary Society blog and all you really need is a couple of index cards.
Now if you want to get fancy, grab one of those Amazon boxes, grab a shoebox, grab a box and put the pinhole in one end of the box and put a piece of white paper on the other end of the box and look through the side of the box to see the sun projected inside the box. This is perfect for little kids. Keep the back of their head pointed at the sun. Put sunscreen on. We don’t want to “lobsterfy” everyone in North America. Put sunscreen on. Wear sunscreen. I just keep repeating that. Wear sunscreen and, if you’re someplace with Zika, wear bug spray as well and keep your kids safe.
Fraser: And so the last thing is let’s talk a bit about some kind of magnification because the sun will look really cool in a pair of binoculars, but that gets especially dangerous. So, what do you need to do to make sure that if you’ve got binoculars or a small telescope – something like that – that you’re gonna be able to make sure you protect your vision?
Because if you look at the sun through a pair of binoculars, it’s not just like you’re gonna just make your eyes sore. You will cook the meat of your eyeballs with a pair of binoculars in just in a heartbeat and that’s permanent. So, if you are gonna want to look through binoculars or a telescope, you gotta make absolutely sure you’ve got a safe environment to do it.
Pamela: So, the safest, safest, safest thing that you can do with binoculars is project the sun on paper on the ground and do not ever turn your head towards the sun.
Look at where the sunlight is coming out of the binoculars and, if you can, attach funnels or if you go to 7-Eleven or KwikStop and get a 64 ounce moose-sized soda, cut a bottom in the soda cup – after drinking all of the soda and becoming very caffeinated – cut a hole in the bottom that your eyepiece fits through. Put a piece of paper on the front of the cup and you can just project the sun onto the front of that cup. This is basically the cheapest way you can make a solar funnel. You can do the exact same thing to a telescope.
Fraser: Yeah, and I like to take a pair of binoculars – again don’t look through the binoculars – cooked meat – remember I just said that – but take the binoculars and you will, if you hold it in the general direction of the sun, you’re gonna see this sort of circle of light that’s coming out of the end of the eyepiece side of the – or sorry – yeah the eyepiece side of the binoculars. So, that is your sun and during eclipse time, that circle that is getting projected will actually have that Pacman chopped out of it as it happens. In fact, if there’s sunspots, you will actually see them. So, you just project it. So, you just you dig in.
You’re not looking through the binoculars or the telescope. You’re holding it at arm’s length and you are pointing it away from you so that everyone in the room can sort of see me doing this and so that the light is landing on a piece of paper and then you will be able – everyone can then look at the piece of paper together and see how this is changing over time. Now, the only downside of that is if you leave it pointed at the sun for too long, you can melt out the optics inside of your binoculars or your telescope if it got glue and things like that.
So, I’ve ruined a telescope this way because I’d set it up and viewed the sky for one day and then I left my spine scope in position and then the next day, the sun came through, but it just was there for 20 minutes and it just melted the inside until it weren’t never right. But again, don’t look through them. Just project it onto a piece of paper. It’s very effective and I really like that because it is a magnification of the sun and you really get to see those really great features and a lot of people can all look at it at the same time.
Pamela: And there are filters out there that you can get. It’s probably too late.
Fraser: Yeah, yeah.
Pamela: So, if you happen to have a 16 stop neutral density filter, that’s what you need is 16 stops of neutral density.
Fraser: And the most important thing is that the filter goes on the front end of your telescope or binoculars. So, you do not filter the eyepiece side of it. You filter the front side, which is bringing in all of the light. So, if you’re trying to put something in front of the eyepiece before you look up and don’t put your sunglasses on or your solar glasses on and then look with your binoculars because now you’re back to cooking the meat on your eyeballs. I really want to get that concept across to all of you.
Pamela: If you don’t like your eyeballs and you want to smell cooked flesh –
Fraser: Yeah, so the key is filters in front on the part that’s away from you of your telescope – that is what’s safe – not on the other side.
Pamela: And we actually have a video up on our CosmoQuest Twitch channel on how to make a solar filter with a telescope and stop down on your telescope so you don’t melt it. You can melt a Celestron I sky scope will start smoking in under ten seconds when pointed without being stopped down at the sun. I know this from personal experience. You need to stop down on your telescopes. We have instructions on how to do this. Go to Twitch.TV/CosmoQuest.
Fraser: Perfect. And then, you will have enjoyed the eclipse. Now you’re gonna be in traffic trying to get back to wherever it is you’re gonna stay. You will join this rare group of human beings around the world that have witnessed and experienced this monumental event with your own eyes, brain.
There are those who have never seen eclipses and there are those who have seen them and then they will want to chase them forever. So, our hope is that we will all be able to join that elite club and be the kind of person who’s actually seen it. So, I’m really excited. I’ve never seen one. I haven’t even gotten rained on one. I’ve only seen partial eclipses. So, this is gonna be – this is our moment.
Pamela: This is our moment. So, go out and the next thing that we’re gonna do is we’re gonna practice all of this stuff and those of you who are listening to this online, go outside, practice too and know that you’re doing the same thing we’re doing here. So, thank you all for joining us for this impromptu special episode and go forth and enjoy the sun with sunscreen and be safe.
Fraser: And let us know how it goes for you. We want to hear. Alright.
Duration: 32 minutes