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Stargazing in August in San Diego

Audio

Aired 8/17/09

August is a great month to stargaze. We'll find why San Diego County has some of the best places in the country to explore the night sky.

These Days guest Dennis Mammana, an astronomer, writer and photographer, captured the starry splendor of the summer night sky.
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Above: These Days guest Dennis Mammana, an astronomer, writer and photographer, captured the starry splendor of the summer night sky.

MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh, and you're listening to These Days on KPBS. This time of year, large groups of people always head out to the Anza-Borrego Desert to enjoy the showers. Not the usual wet kind, of course, but the astronomical twinkly kind. The annual Perseid meteor shower peaks in mid-August, and it is an annual treat for star parties and groups of amateur astronomers. But, as we will hear, the meteor shower is only one of the wonders of the night enjoyed by summer stargazers. This is a great time of year to get a full view of the night sky in the desert, or to see Jupiter up close and personal at Palomar Observatory, or to grab a pair of binoculars go out in the backyard and see if you can spot the red supergiant Antares that is the heart of the constellation Scorpio. But what if you know nothing about the night sky, where do you begin? Well, you may just pick up a few tips right here from my guest Dennis Mammana. He's astronomer and night-sky photographer who lives in Borrego Springs. He also writes the weekly Stargazer column in the San Diego Union-Tribune. Dennis, welcome to These Days.

DENNIS MAMMANA (Astronomer): Thank you. Thank you for having me.

CAVANAUGH: We're inviting our listeners to join the conversation. Are you an amateur astronomer? Tell us why and where you like to go to look at stars. Call us with your questions and your comments. The number is 1-888-895-5727, that's 1-888-895-KPBS. Well, Dennis, why is August a good month to stargaze?

MAMMANA: Well, it's hard to say that August is the best month to stargaze but it's warm, people are off of work, vacations and school holidays and so on, and people travel and they can get away from the city. They have time to do so. So August is a really good month and, plus, the fact that in the summer sky, in the August sky, in particular, over at least the northern hemisphere of the Earth, the Milky Way is at its biggest and its brightest and its best and so it's an absolutely glorious sky and it's a great time to get out into the wilderness to do stargazing.

CAVANAUGH: Now I mentioned the Perseid meteor shower but that's – You told me that's over.

MAMMANA: That actually peaked last Wednesday morning…

CAVANAUGH: Uh-huh.

MAMMANA: …before dawn. There are still a few straggler meteors that you can see but it's pretty much over until next year. We will have other meteor showers later this year in mid-November, the Leonid shower could be a very, very good one. And in mid-December, the annual Geminid shower is often the year's best. People don't typically get out in December because they're afraid of the cold but the Geminids will draw you out if you ever get a chance to see them.

CAVANAUGH: Now is there a like year-to-year like that was a really good meteor shower or that wasn't that hot that year – this year, I mean? Are some years better than others?

MAMMANA: Oh, absolutely. This year's Perseid shower, for example, was excellent. It was far better than in previous years and there are some physical reasons for that. There is a good possibility the Leonid shower in November will be very good but the last few years it has not been. So, yeah, we are passing through swarms of dusty material in space—that's what causes the meteor shower—and sometimes those swarms are very dense and fall into the atmosphere prolifically and sometimes there's just nothing. And I've sat outside occasionally during meteor showers and wondered why I was there.

CAVANAUGH: Uh-huh.

MAMMANA: There's just nothing falling. And sometimes the sky opens up.

CAVANAUGH: And that is because…? What are the physical reasons for that?

MAMMANA: Well, we're – The Earth is passing through swarms of dusty material most often left behind by comets. And the dusty material is not spread evenly across their – the orbits of these comets. There are clumps. And so sometimes we pass through clumps of the material and we get a great shower and sometimes we pass through relative voids. And they are somewhat predictable but, you know, you pays your money and you takes your chances basically.

CAVANAUGH: I'm speaking with Dennis Mammana and we're talking about astronomy and what you can see in the August sky. 1-888-895-5727, if you'd like to join the conversation. Dennis, why is Southern California – Well, let me ask you this. Is Southern California a good place to watch the night sky?

MAMMANA: Southern California is a great place to watch the night sky. It's – We have a very large population here but we also have a lot of places where one can go to get away from the city lights. We have the mountains. In San Diego County, of course, we have the Laguna Mountains and we have the Palomar Mountain, and we also have the deserts, which, in Anza-Borrego Desert in the main one in San Diego County. These are places that are very, very dark and are excellent for stargazing. Amateur astronomers flock to these places because it's a perfect place to look at the sky.

CAVANAUGH: And is Anza-Borrego basically the best place, would you say?

MAMMANA: Well, I'm a little biased since I live there. We have recently been designated by the International Dark Sky Association as the only or, right now, the first International Dark Sky Community in California—we're actually only the second in the U.S. and second in the world—because of our dedication to preserving our night skies and because it is such a dark place. It – Whether it's the best or not depends really on what you want to do. If you live on the coast, for example, and you don't want to drive two hours, the Laguna Mountains, for example, would be better simply because they're closer. But if you have a couple of days or if you want to – if you like the desert weather and you like the dryness and you like being in a community as opposed to up on a mountaintop someplace, then Anza-Borrego is definitely the top choice.

CAVANAUGH: Now I have to ask you more about that Dark Sky Community designation. There really has to be some thought and planning into this. Somebody just doesn't come around and say, oh, okay, this is a good place to see the…

MAMMANA: No.

CAVANAUGH: …the night sky. This is a dark sky place. You – The community has to be actively involved in actually getting that designation.

MAMMANA: Very much so. And…

CAVANAUGH: Tell us a little about that.

MAMMANA: Well, in Borrego Springs—I'm very proud of that community—we have people there that are not only dedicated to the desert below them but also to the desert above them. That's one of the things that I always tell people, is that our desert environment is 360° around us. We have the desert below from the horizon down but I'm most concerned with the desert from the horizon up. And whereas everyone is interested in protecting that pristine desert environment from the horizon down, people now are becoming far more interested in the desert above as well. And that's why we put a small task force together two years ago to get community involvement, to put an application together to the IDA and just this last week we got our designation, and so it took two years. We are, like I said, the second International Dark Sky Community that's been designated. The first was Flagstaff, Arizona. There are a lot of astronomical observatories around there. That was in 2001 and we, in 2009, are the second.

CAVANAUGH: Wow.

MAMMANA: So this is not something that's easy to get and it's something that we're very – quite proud of.

CAVANAUGH: People have to promise that they'll put in a special kind of lighting in their homes and direct their ho – I mean, outside lights in their homes. And you have to make sure that the lights are directed in a certain direction. Is all of that right?

MAMMANA: Well, it's purely voluntary, of course.

CAVANAUGH: Right, right.

MAMMANA: I mean, we're not going to be the lighting police and go out and ticket people.

CAVANAUGH: Right.

MAMMANA: But it's purely voluntary. But we do have a – like I said, a community that's very dedicated to the preserving the night sky and so we've had resorts, we've had businesses, we've had individual homeowners, we've had development – or, apartment communities and so on, come to us asking us to evaluate their lighting because they wanted to make changes to become more night sky friendly. So it's purely voluntary but the community is so far – so much behind us that I think it's going to be relatively easy to keep this going.

CAVANAUGH: Well, I have to ask you to describe what the sky looks like now that this is a Dark Sky Community. What is the difference? What can you see when you look up at night now?

MAMMANA: Well, we had an event a couple of nights ago out there and we had – many, many people came from San Diego and elsewhere. And everybody had the same reaction, you know, I could never see any of this in San Diego or anywhere else. You step outside here, you see a few stars, maybe a planet or two, certainly the moon if it's up. But out there, the moment you step outside and look up, the Milky Way is this beautiful hazy veil that drapes overhead in this dark sky. You've got stars that you could never see before, so many of them that people have a hard time finding their way around the sky even though you point things out to them. So whereas we are not the darkest place in the world, I mean, you can go to the top of the Sierra Nevada, you can go out into the middle of Death Valley, you can go to the Atacama Desert of Chile, and you will see much, much darker skies. That's not what the designation is. The designation is that we are devoted to preserving what we have and we have a community there, so that designation is important because it drives us to help preserve it. You got to realize, Borrego Springs is – we're out in the middle of the desert but we're surrounded by one of the largest population densities on the planet, you know, LA, San Diego, El Centro, all surrounding us and yet we are this dark jewel, if you want to call it that, surrounded by a thousand square miles of desert, surrounded by mountains on three sides. So within two hours from almost anywhere, you can have an almost pristine sky.

CAVANAUGH: I am speaking with Dennis Mammana. He is an astronomer, night sky photographer, living in Borrego Springs. And he writes the weekly Stargazer column in the San Diego Union-Tribune. We're taking your calls about astronomy. Any questions you might have, any comments you have about why you like to look up at the skies. 1-888-895-5727 is our number. I want to ask you a little bit, Dennis, all right, so you can see the night skies. What are you seeing in them in this summertime? You mentioned a really good view of the Milky Way. Tell us more about that.

MAMMANA: Well, the Milky Way is absolutely stunning. On a good dark night in the desert, it's absolutely stunning. You've got this wispy band of light going across the sky. It's not evenly illuminated. There are dark rifts that run through it that – like these little rivers and little canyons that run through this thing that are dark. These are actually dark clouds that we see in silhouette. And you can watch it, you can follow it from horizon to horizon. This is the plane – the geometric plane of our Milky Way galaxy in which we live, and most people have never seen it. In fact, I've had people come out and it gets dark and you're ready to start pointing things out in the sky and they will say – They'll look up and see the Milky Way and say, well, looks like it's getting cloudy, I think I'll go in. And I scream, no, don't do that. That's what we're here to see. So it is – it's pretty amazing. If you get to see the August sky in a dark sky, anywhere in the Northern Hemisphere where it's really, really dark, it's breathtaking. It's really one of the very best of the year.

CAVANAUGH: What else do you point out to people at this time of year?

MAMMANA: Well, in this particular August, the planet Jupiter is very, very bright in the sky, in the southeastern part of the sky just after dark, you can see it. It's the brightest thing over there. A lot of the things I point out are certainly constellations, things that people might never have seen before. I tell stories about – some of the behind the scenes stories of astronomers and what they're actually looking at. And, of course, with telescopes, you can see things like globular star clusters and interstellar nebulae where planets and stars are constantly being born. We can see binary stars of different colors. It's a remarkable sky. And then, of course, this August now everybody is expecting, on the 27th of August, to go outside and see Mars, big and bright.

CAVANAUGH: Big, bright Mars.

MAMMANA: Big, bright Mars and, boy, are they going to be disappointed.

CAVANAUGH: Why?

MAMMANA: Well, in fact, my column in today's paper explains it. But if you have a computer, you have probably received the e-mail saying Mars will be as big as the full moon this month. And the fact is that that's all bogus information. It can never happen. And just pick up the U-T today and read the column but basically it's bogus. If you want to see Mars, you can see it but you have to get up before dawn, you have to go look to the east, and it is about as small and faint as it will ever be.

CAVANAUGH: Oh.

MAMMANA: Completely opposite of what people have been told by this bogus e-mail. This has become a…

CAVANAUGH: Ahh…

MAMMANA: This has become an urban legend. In fact, you can go to Snopes.com and you can read all about it. It's something – And with the internet being what it is, this is going to come around every summer from now until the sun burns out so – But that's one of those things. But people come out and expect to see that, and I have to explain, no, this is, you know…

CAVANAUGH: So…

MAMMANA: …you've been had.

CAVANAUGH: …of all the things they can see, they're looking for the one thing they can't see.

MAMMANA: They are, and you can see – certainly see Mars but it's not what you expect it to be.

CAVANAUGH: Let me take a phone call. Lots of people want to talk to you. Lesley is calling from San Diego. And good morning, Lesley. Welcome to These Days.

LESLEY (Caller, San Diego): Good morning. I was outside a couple of months ago and I was coming home rather late at night and I looked up and noticed the moon was really full and bright. But outside of the moon, it had like a glow, almost like a giant halo surrounding it, something I've never seen before. And actually I sat out there for about a half hour and just looked at this because I was so intrigued. Do you know what that might have been or what would have caused it?

MAMMANA: Well, it depends on what you mean by halo. It was not touching the moon, right? It was separated from the moon?

LESLEY: It was separated from the moon and just simply just surrounded the entire moon though. And when I put my hand up, I'd say it's probably the whole width of my hand…

MAMMANA: Okay.

LESLEY: …or the length of my hand so obviously it was large.

MAMMANA: That's a very good observation and it's a good measurement, too. That's great. That really helps. What you saw was – is something that's called the halo. You can see those halos around the sun or the moon sometimes. What you need are cirrus clouds in the sky, those very thin, wispy clouds that we get sometimes preceding storm systems. And when they come in, if you have a light source in the sky like the bright moon or like the sun, you can sometimes see those halos around them and they're really very, very pretty, you're absolutely right. And they're not that unusual around here, quite frankly.

LESLEY: This is the first time I've ever seen it and certainly to that extent and I just couldn't get enough. I had to go inside and wake someone up and say, come outside and take a look at this.

CAVANAUGH: Thank you, Lesley. Thank you for your call. Let's talk now with Tim in Carlsbad. Good morning, Tim. Welcome to These Days.

TIM (Caller, Carlsbad): Yes, hi. Yeah, a few years ago I was watching a meteor shower and I saw a meteor that exploded or popped and I was wondering – I couldn't hear it but clearly something happened. I was wondering could there have been some kind of trapped gases in the rock that, you know, heated up when it hit the atmosphere and caused it to explode like that? Or what would be a plausible explanation for something like that?

MAMMANA: Well, that's entirely possible. These things mostly are specks of dust that hit the atmosphere and when they hit the atmosphere, they're hitting at approximately, oh, 30 or 40 miles per second. Now they're coming from the vacuum of space and when they slam into the atmosphere they create a tremendous shockwave and they superheat the air that – and that's basically what you're seeing. But it could very well have been some kind of a shockwave that went through the speck of dust, maybe it was something as large as, oh, maybe a garden pea, for example, and it's possible maybe there were some trapped gases inside. I really don't know. I'm not a meteorite expert. But these things that you see are called fireballs. That was definitely a fireball. And occasionally one of these things will hit the atmosphere so hard or explode and you can, in fact, hear the sound. Those are called bolites. But remember, these impacts occur about 50 miles up so you don't hear the sounds. If you do hear a sound, you don't hear it instantly. It takes a few minutes for that sound to make that journey if it can even make the journey through that thin air.

CAVANAUGH: That's fascinating. Byron is calling from Encinitas. Good morning, Byron. Welcome to These Days.

BYRON (Caller, Encinitas): Thank you. Good morning. Enjoying the show.

CAVANAUGH: Thank you.

BYRON: I just wanted to share an experience I had about dark night sky. Last time Halley was here, I put the kids in the back of the car and went down Mt. Laguna to watch and when I got there, I was very disappointed. There were a bunch of cars around and I looked up and I thought this is terrible. There's all these – There's this heavy cloud where Halley's going to come up. And I looked for it for a minute and realized it was the Milky Way and I just never see it like that over here on the coast and just quite a testament to what going to some dark sky can give you an experience that you would never expected (sic).

CAVANAUGH: Byron, thank you so much. Thank you for calling. That's exactly what you were saying.

MAMMANA: Yep.

CAVANAUGH: It's getting cloudy. No, that's what we're here to see.

MAMMANA: Absolutely.

CAVANAUGH: You know, Dennis, there's going to be a star party in Julian…

MAMMANA: Yes, this weekend.

CAVANAUGH: …Julian Starfest is happening this weekend.

MAMMANA: Umm-hmm.

CAVANAUGH: What goes on at these parties?

MAMMANA: Well, a star party, I mean, it sounds like you're going to have, you know, drinks and chips and stuff like – And that's not what – that's not what it is. Star parties typically where when amateur astronomers come out, set up telescopes, allow you to look through their telescopes, and it's a really wonderful evening. But the Julian Starfest, the second year that they've been doing it, it's very, very popular so far. They will have lectures, they'll have other activities, they will have – there's a tour to Palomar Observatory, which I understand is sold out. In fact, I will be doing one of the lectures on Saturday afternoon. But it's a full day of events on Saturday. Friday night there are some programs, Saturday there's full – full day of programs plus stargazing and so on, then Sunday it's kind of wrapping up. But there are a number of these around the county during the course of the year. Julian Starfest is this weekend and I encourage everybody to get up there. In November, we in Borrego have one called Nightfall. And in May of each year, up in Big Bear there's a – there's one of the biggest in the entire country called the Riverside Telescope Makers Convention. And there's one in Pasadena, and various places. But, yeah, the Julian Starfest coming up this weekend should be a lot of fun, a lot of things to do for people.

CAVANAUGH: Let's take another call. Richard is calling These Days. Good morning, Richard. Welcome to These Days.

RICHARD (Caller): Thank you very much.

CAVANAUGH: How can we help you?

RICHARD: I was fascinated by the designation of Borrego Springs as a Dark Sky area and I was wondering if the hospitality industry has gotten onboard, specifically if there are places where a coastal dweller can go out, spend the night, and be assured that this is lodging that's particularly suited for stretching out on a couch with a pair of binoculars or a small scope?

MAMMANA: You should have no problem there. Now we do have several of the resorts there that have taken some active steps to actually change their lighting a little bit to darken it up a little, obviously keeping it still safe. You've got to keep it safe on the ground but aim the light downward. And then there are some that are – that have asked us to come out and check out their sites and recommend some things for them. But Borrego is so dark anyway that you will not have a problem in any of these resorts. I mean, I don't know how many communities in the United States where you can stand in the parking lot of the U.S. Post Office, look up and see the Milky Way. So the resorts themselves, the hotels are relatively dark and, in fact, if you wanted to just go a little bit farther out, you can get it even darker.

CAVANAUGH: I'm wondering, you know, suppose someone really can't or doesn't want to make the trip out there and wants to do a little gazing at the night sky right here in San Diego. Do you actually – Do you need some sort of telescope to be able to do that?

MAMMANA: Not at all. No, astronomy is one of those hobbies where you can – you can spend a fortune, you can mortgage your home to buy stuff, or you can just go outside and look up. One of the advantages of being in the suburban area of San Diego, not specifically downtown, although you can still see a few stars from there, but in the suburban areas, is that the light pollution does scatter throughout the sky and does diminish the number of stars you can see but that can actually be an advantage for beginners because then you're not overwhelmed. You can find some of the brighter star groupings and constellations. So – But you do not need a telescope, absolutely not. What I recommend in the classes that I teach, the backyard astronomy type classes, is I recommend people learn the sky first with the naked eye and then when they feel they understand it fairly well, then graduate to binoculars. And then if you're really interested in it, then you will have learned enough about the sky and optics to know what kind of a telescope you need to buy. Because what typically happens is if people buy a telescope before they're ready for one, I guarantee you, 95% of people, it winds up in the closet sitting there next to the NordicTrack. And it does because it's – you don't know how to use it, and if you don't know where to aim it, it's pretty worthless. It's a giant paperweight.

CAVANAUGH: And, as you say, if people get used to the night sky just looking at it and perhaps using some binoculars, and then they go out to an area where there is this – a dark sky, a really darker sky, they actually may become completely confused.

MAMMANA: Oh, there's no question about it. And I've been in that situation before…

CAVANAUGH: Uh-huh.

MAMMANA: …where I've been to places that were so pitch black that I literally could not find the Big Dipper, which I have been finding since I was six years old. It was so – I mean, I remember in 1986 going to the northern mountains of Mexico to – with a group to show them Halley's Comet and I was absolutely flabbergasted. I could not find the Big Dipper. Now, eventually I found it. But I was overwhelmed by it, and I can imagine a beginner. You know, they're going to look up and they're going to go, oh, this is – this is crazy. So I would recommend finding a couple of books on astronomy. Take a class or two. I teach a number of classes. There's the San Diego Astronomy Association. If you live in some of the outer lying communities, they've got astronomy associations. Get involved with them. Take some classes. Read some books, magazines. And eventually you will learn the sky just with the eye.

CAVANAUGH: Well, Dennis Mammana, you've given us all something to do.

MAMMANA: Well…

CAVANAUGH: Thank you so much.

MAMMANA: You're quite welcome. Glad to be here.

CAVANAUGH: I've been speaking with Dennis Mammana, astronomer and night sky photographer. He writes the weekly Stargazer column in the San Diego Union-Tribune. We urge you to post your comments online, KPBS.org/TheseDays. Thank you for being with us and stay with us as These Days continues here on KPBS.

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