Sun-Earth Connection Education Forum Podcasts
Transcript of Sun-Earth Day 2006 Podcast, Program 6
Welcome to the sixth in a series of NASA podcasts that will explore solar eclipses, and how humankind's fascination with the moon has been evident throughout history. Today is March 28th, 2006. My name is Troy Cline on location in Side, Turkey. In this podcast, I will introduce you to two instrumental members of our webcast crew, Senior scientist and cohost Paul Doherty, and video systems coordinator Larry Kenworthy. My first interview started with a question to Paul.
Troy: How many eclipses have you seen?
Paul: Well, I've seen five solar eclipses, and one annular eclipse. If you want a collective noun for total solar or annular eclipse, it's called a central eclipse, and that's when the moon is centered in the Sun as it comes through . versus a partial eclipse where part of the moon touches the edge of the Sun.
Troy: Now, can you describe a few safe methods that people who are especially in the Path of Totality can use to view the eclipse?
Paul: There are two things you should remember and that is, you should never look at a partial Solar eclipse no matter how little of the Sun is showing with your naked eye. The Sun is just too intense and you have no pain sensors in your eyes. So you can damage your eye and never feel any pain until you go blind. So you must use safe viewing techniques. One thing you can do is to put down a white piece of paper on the ground, and then take a piece of cardboard and punch a little hole in it, like with the tip of a pencil, a hole maybe an eighth of an inch across. And then cast a shadow with that board with the hole in it on to the white board on the ground. And the Sunlight will come through the hole and make a pinhole image of the partial Solar eclipse on the white board on the ground. It's a completely safe way to watch the partial eclipse.
Troy: Now I understand that also sometimes when an eclipse is occurring, that when the light is shining through the branches of a tree, that it casts several shadows of an eclipse across the ground. Is that correct?
Paul: That's correct. It's wonderful actually. You probably haven't noticed that the light that comes through tree leaves on to the regular flat ground is made of circles. They are circular images of the Sun, and people just don't notice that. But during a partial Solar eclipse, it's made of crescents. And when you see the ground covered by crescents, it's just a shocking experience. It's quite wonderful. So you must look down at the ground during a partial eclipse as well.
Troy: I overheard you talking earlier today about something called shadow bands, and that is new for me and I am sure many people have never heard of shadow bands. Could you describe that?
Paul: Shadow bands occur right at the end of the partial Solar eclipse when the Sun is reduced to just a slit of light. And that slit of light coming through the atmosphere on to a flat surface of the ground like sand, makes something that looks like wooly bear caterpillars the size of my arm, rolling sideways across the ground. They're shadows, and they just move across the ground. They're easy to see with the human eye, they are almost impossible to photograph.
Troy: And you.ll be trying to capture that during this eclipse I understand?
Paul: That's right! Phil Morrison, my professor from MIT taught me to bring a large white sheet to an eclipse, put it on the ground, and then look on the sheet for shadow bands before Totality and after Totality at the very edges of the partial eclipse.
Troy: Paul, can you describe what we.ll be seeing?
Paul: Well, if you just look around you during an eclipse, the light starts to go strange after about ten percent of the partial Solar eclipse, and it gets stranger and stranger. When half the Sun is covered you know something weird is happening. And as you get close to Totality, the light just becomes sort of reddish and dark, yet the sky is completely cloud free, and it's getting dark. It's a very strange feeling. And then, during Totality, It's spectacularly strange. The Sun goes out, you look up at the sky. The sky is dark, the stars will come out, the white Corona of the Sun will reach out as your eyes adapt to the dark from the Sun like a big fat white spider reaching its legs out.
Troy: Wow!
Paul: Were in the quiet Sun right now, on the Sunspot cycle, and that means we.ll have maybe organized streamers. Great plumes coming out of the Sun for long distances. So I'm looking for those.
Troy: And what is the term used for the type of streamer you are describing?
Paul: Well, they're called helmet streamers because they look like a Greek or Roman helmet where the helmet curves over the head and then comes up in a crest on the top. So, from the Sun, there will be this, like a helmet coming out of the edge of the Sun and then a streamer going out from that.
Troy: Paul, I understand you had quite an explosive eclipse story and experience. What was that all about?
Paul: Well, one of the eclipses I went to was in Chile, in the Atacama desert. And I am a mountaineer, so I went to climb a volcano, and when we got there we watched the eclipse over the volcano, which was wonderful, except, the volcano was erupting at the time.
Troy: Oh No! (chuckles)
Paul: So I got to watch a total Solar eclipse while standing in the middle of a herd of Alpaca over an erupting volcano.
Troy: Oh my goodness (chuckles)
Paul: You've got to travel sometimes!
Troy: My next interview was with Larry Kenworthy, the video systems coordinator for the webcasts. I asked Larry to describe his role.
Larry: During the webcast itself, I will be switching the telescope feed that basically sends the four different views of the eclipse back to the satellite which then disseminates the show to the various websites that are going on, and also the live television programs that are happening at that time. During the eclipse, I usually will switch the telescope feed. We have two separate feeds . one is the actual show feed which includes the scientists, and their descriptions of the event and what's going on at the time. And then we also simultaneously send a second feed that is just shots from our various telescopes. We have four telescopes that we brought with us and three different kinds of filters. And we basically will have a full bandwidth satellite feed coming back to the NASA web center that is switched from time to time from these different views. Integrating video with the telescopes so that we can bring these pictures to lots of folks is kind of a delicate process. LCD technology has been improving and growing over the recent years, and we use several adaptors and so forth to adapt the LCD cameras directly to the back of the telescopes. And we use broadcast quality three chip LCD cameras that can be fully controlled and synchronized and so forth for our program. And they are very unusual, they work very well. And then with the telescopes we also bring usually various types of filters. We have to bring special filters of course to observe the Sun with our white light telescopes, but we also bring H Alfa filters, and this year we are adding a calcium K filter so that we can have hopefully some unusual and exciting views of the Sun for the total eclipse and after.
I think my favorite eclipse story happened in 1999 when we were in Amasia, Turkey, doing an eclipse, and we.d had some trouble with the weather. But prior to the weather, when we were setting up our video control room in the downtown square, a local city worker climbed a power pole for us to provide us with power, and just wrapped raw cable, raw copper cable around the power lines going through downtown Amasia, and then brought those lines down to us, which we then measured and adapted into our system. But it was very dangerous and we were also surprised that he would climb a metal power with these copper cables to hook them up. But anyway, what ended up happening, about three minutes before the eclipse, our little power strip that we were using to distribute the power to the various pieces of television equipment caught fire from the power that was being fed to us.
Troy: Oh no!
Larry: The engineer, Erin Rosen and I just kind of had to dive on this little fire and put it out, and quickly ascertain what pieces of equipment were damaged, and then work around them so when the first contact happened and the eclipse began, that we were back in good shape.
Troy: So you really throw yourself into your work? (laughs)
Larry: Sometimes we are definitely thrown into our work, not by choice always. We try and plan around fires when we're doing these eclipses.
Troy: Sun Earth Day is a program sponsored by the NASA Sun-Earth Connection Education Forum at the Goddard Space Flight Center, and at the UC Berkeley Space Sciences Laboratory.
To find out more about the Sun Earth Day program and eclipses, visit our website at sunearthday.nasa.gov
This is Troy Cline signing off
