Archive for October, 2010

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Birthplace of suns

October 16, 2010

Normally I loathe just reblogging stuff from elsewhere on teh t00bz, but I make exceptions. Sometimes it’s nice to have your sense of wonder not just tickled, but smacked right across the room. This picture of NGC 346, from APOD, did it for me. Click through to the astronormous hi-rez version, and spend a few minutes zooming in and out. While doing so, try to hold these two ideas in your head at once: first, this is just one star-forming region in the Small Magellanic Cloud, which is a small satellite galaxy of the Milky Way, which is a big spiral galaxy in a small galaxy cluster on the outskirts of a not-terribly big supercluster, and so on and so forth; and second, every star in the picture is a sun, each with its own history and fate, most with their own systems of planets–and so on and so forth.

If NGC 346 was our entire universe, we could spend a thousand centuries exploring it and not exhaust its wonders. And yet you would not have to venture far into the closer galactic superclusters to find more galaxies than there are stars in the photo, each galaxy with more stars than you could count in a lifetime, each star with its own unique history.

Right! Enough of that! Back to fighting over our speck of dust.

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Observing report: the backup star party

October 11, 2010

Saturday afternoon London and I drove to the Mojave Desert east of Barstow, California. We caravanned with our friends Jann and Gene, whom Vicki and I have known since before London was born. The San Bernardino Amateur Astronomers, Pomona Valley Amateur Astronomers, and High Desert Astronomical Society were all coming together for a big star party at Afton Canyon. We missed that; the road down into the canyon had a few rocks big enough to potentially eviscerate my Mazda5 and Jann’s and Gene’s Honda Fit, so we camped up on the canyon rim. In the photo above, you can see some white picnic shelters down in the canyon.

As it turned out, we had a fabulous evening even though we missed the official star party. We were just getting set up before dark when a sedan pulled up next to us, which turned out to hold my friend and fellow PVAA member, Gary, and his 13″ Coulter dobsonian. I had my 10″ Orion dob and a 5″ widefield reflector a tripod, and Gene had brought along his Celestron C90, so we had plenty of telescopes. This would prove fortuitous. We had just a few minutes to catch the very young crescent moon before it set, and then ate dinner while we waited for twilight to fade.

Jupiter and the Galilean moons, taken with my XT10 and Nikon Coolpix 4500. Click for the big, unlabeled version.

A group of a dozen or so college students from USC were also camping on the canyon rim, fifty yards or so away from us. As I usually do when either camping or observing, I invited them to come over and stargaze if they were so inclined. Many of them took me up on the offer and from 7:00 until about 11:00 we–that is, Jann, Gene, Gary, and I–entertained a steady stream of guests. I had a low-power eyepiece in the 5″ reflector for widefield views of the Double Cluster, Andromeda Galaxy, Pleiades, and other expansive targets. Gene’s Mak was turning in tack-sharp views of Jupiter and some double stars, and Gary and I were serving up deep-sky objects with the two big dobs, with frequent breaks to watch the dance of Jupiter’s moons. I didn’t keep a list of things we observed, but off the top of my head I recall seeing, in addition to the aforementioned targets:

  • M7 and M6, open clusters between the tail of Scorpio and the teapot of Sagittarius;
  • M8, the Lagoon Nebula, and M20, the Trifid Nebula, in Sagittarius;
  • the M24 star cloud;
  • M11, the Wild Duck Cluster. This was a sure crowd-pleaser.
  • Ditto for M13, the Great Globular Cluster in Hercules;
  • More globs: M22 in Sagittarius and M15 off the nose of Pegasus;
  • Planetary nebulae: the Ring (M57), the Dumbbell (M27), and the Cat’s Eye (NGC 6543);
  • NGC 253, the Silver Coin Galaxy;
  • NGC 457, the ET Cluster, in Cassiopeia;
  • Brocchi’s Coathanger, an asterism near Cygnus;
  • Mizar & Alcor, a multiple star in the handle of the Big Dipper;
  • Epsilon Lyrae, the “Double Double” star, Lyra.

These were just the things we had in regular rotation. I also had my green laser pointer and was using it to point out the constellations and some of the brighter deep-sky objects. M7, M8, M20, the Andromeda Galaxy (M31), the Double Cluster, and Brocchi’s Coathanger were naked eye visible. It was also a cinch to get people on target with binoculars by pointing with the laser and letting them follow the beam. I had along three pairs of binoculars, 7×35, 7×50, and15x70, and they all got used.

We were seeing shooting stars throughout the evening, and I saw two that produced visible flames and left glowing trails across the sky. The sky, by the way, was very dark and very clear, probably the finest sky I’ve had for a big-scope observing session. The Milky Way was amazingly detailed to the naked eye even before the sunset had completely faded.

The group observing wound down sometime around midnight. Our last few targets included nebulae in and around Orion–M42, M43, and the sometimes elusive M78–and the galaxy pair of M81 and M82. By that point I was tired of driving the big scope and also just plain tired, so for my last hour of observing I curled up in a camp chair with the 5″ reflector and just did some casual solo stargazing, with no plan or fixed destination.

My favorite views of the evening were:

Number 3: seeing riffled edges on Jupiter’s cloud belts (the photo above does not do it justice), in the big scopes.

Number 2: seeing the Double Cluster surrounded by an incredibly rich Milky Way starfield, in the 5″ widefield scope. I prefer to observe the Double Cluster with a wide enough field to get some nicely frame the two dense conglomerations of stars and to give some context. Prior to Saturday night, my all-time favorite view had been with 15×70 binoculars from Mount Baldy. The view in the 5″ scope was like binoculars on steroids–a nice wide field, but packed with wall-to-wall stars. I got that sensation, which I crave, of having so many stars in the eyepiece that it was almost exhausting to take it all in.

Number 1: dust lanes in the spiral arms of M31. I first saw these for myself a couple of months ago out at Owl Canyon. Now that I know what to look for–and since I keep going to progressively darker sites!–these get easier and easier to spot. To me, it looks like someone got charcoal on their hands and dragged two fingers across the galaxy. The arms don’t show up as denser concentrations of light, but interruptions in the soft glow of the galaxy; not brighter but darker. I could see these in the 5″ scope, and they were sufficiently clear in the 10″ scope that people with no prior observing experience were seeing them right away. I remember how much of a kick in the brainpan it was when I first saw those spiral arms, and it was awesome to get to share that with others.

In fact, having people to share the views with really made the night. If it had just been Jann and Gene, Gary, and London and me, I’m sure we would have had a nice time. But it was so much nicer to have interested people stopping by to show things to. I’d say that my enjoyment of telescope time scales directly with the number of people I get to observe with. I can have a fine time all by myself, and it only gets better from there.

Stargazing was only half of the fun, though. This morning we had a lazy  breakfast in camp while we waited for the air to warm up a little, and then we went for a hike.

Gene had a GPS unit and the coordinates of a geocache, which gave us a general direction for the hike and an achievable goal. We followed the road down into Afton Canyon, crossed a dry riverbed under a railroad trestle bridge, and explored a very beautiful side canyon.

Eventually our first route led us to a treacherous slope so we found another way back down to the bridge. We found a stand of rushes and a trickle of water, with lots of dragonflies zooming around. Jann had a field guide to dragonflies along, so she and London watched dragonflies while Gene and I pushed on to the cache. Gene’s GPS  was getting satellite bounce that imparted some meandering to our path. At one point we found some old graves made of piles of rock with weathered, sunblasted wooden crosses, like something right out of the Old West. That was downright creepy, even for someone who works with cadavers. Eventually we did find the cache and sign the logbook, and all four of us enjoyed a leisurely stroll back to camp.

I’ve been fortunate to get out to the desert quite a bit this year–to the Salton Sea on several occasions in the spring, to Owl Canyon a couple of times, and to Joshua Tree Lake last weekend. This weekend’s trip was my favorite so far; the entire time I was exultant at being out at such a beautiful place. I’m already looking forward to next time.

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Observing report: and now for something completely different

October 3, 2010

Last night my son London and I went to a star party at Joshua Tree Lake RV & Campground. The party was hosted by the Southern California Desert Video Astronomers, and it was not like any other astronomical gathering I’ve ever attended. The SCDVA have a nice area of their own off the main campground, with a couple of big white screens on which they project live images taken through their computerized telescopes. It was my first exposure to large-scale video astronomy, and also my first experience with how the SCDVA put on a star party. In short, it actually was a party. There were probably 50 or so people in attendance, and there was an actual program with a series of MCs and live music and a guest of honor.

The guest of honor was John Dobson, who is famous for basically inventing both sidewalk astronomy and the Dobsonian telescope. Dobsonians are just Newtonian reflectors on alt-az mounts, and the name “Dobsonian” was coined by people other than John. In his words, it’s just a cannon mount, and wars have been fought for centuries with big guns on “Dobsonian” mounts. He’s much more proud of having his name attached to Dobson’s Hole, which is what we Dob drivers call the area of the sky straight up overhead, because it’s such a pig to accurately point our scopes at targets near their axis of azimuthal rotation (frequent adjustments in non-intuitive directions, and no leverage short of bear-hugging the scope or putting handles on the side).

What set John Dobson’s alt-az mounted Newts apart from those that had come before is that they were CHEAP and they were BIG. The cheapness was of necessity–Dobson started building scopes when he was a monk, and the associated poverty meant that he had to scrounge for telescope materials. The classic homebuilt Dobsonian had a thick cardboard tube, of the kind used for forming concrete; a base made out of plywood; and a mirror ground and polished by the telescope maker from a big blank of glass–in Dobson’s case, old ships’ portholes. The bigness was of design–Dobson felt, and feels, that the way to get people hooked on the wonder of the universe is to kick them in the brainpan with the view of some celestial object through a great big telescope.

Dobson’s other great invention (or popularization, if you prefer) was sidewalk astronomy. As with the Dobsonian mount, public outreach by astronomers had a long history, but Dobson kicked it up a notch. Before John Dobson, astronomy outreach usually involved bringing people to the telescopes. Dobson brought the telescopes to the people. As he put it last night, he did it to remind people that their address in the universe didn’t end at Haight Street (the famous “hippie” street in San Francisco where Dobson used to set up his telescopes for passersby). Events like International Sidewalk Astronomy Night and Observe the Moon Night trace their roots to Dobson’s brand of engaging the public, and the entire International Year of Astronomy was very much in the same spirit, although obviously much broader.

Dobson–who turned 95 just last month–gave an interview and took questions from the audience, and in all probably spent about an hour speaking. He was very entertaining. My favorite bit:

Woman in the audience: “How did you get interested in astronomy?”

Dobson: “I got born. What’s your problem?”

At that point, surreally, I went on a brief scorpion hunting expedition with fellow PVAA member Cliff Saucier, who had a UV flashlight and asked me if I wanted to see some scorpions. I didn’t know before last night that scorpions flouresce under UV light, but man, they shine like little yellow-green suns. Cliff could wave his flashlight back and forth over the desert floor and from 30 feet out we could see scorpions glowing like flares. The picture is blurry because I took it with my phone, but the colors are faithful, just quite a bit less intense than the live view. You’d swear that the scorpions themselves were radiating. It made them look even more like evil machines than they already do, which is saying something.

Back at the star party, we were treated to a slide show of stunning desert photography and a life performance by “Hurricane” David McChesney, former national champion harmonica player. Now, I am not normally a big fan of the harmonica, but on the other hand, I have never in my life heard anyone play it like Hurricane Dave. For big swaths of his show I was sitting slack-jawed with a big dopey grin on my face, not because he was funny (although he was, frequently and deliberately), but because it’s awesome to see a master working at the top of his game. I was reminded of the quote that the highest levels of performance in any field of endeavor are indistinguishable from art.

After Hurricane Dave, the video astronomy got going. While the SCDVA guys put up one stunning image after another, Clive Wright played his spacey ambient guitar. It was far out, man, and I mean that as a compliment. Up on the big screens we got to see the Ring Nebula, the Dumbbell Nebula, the Swan Nebula, the Lagoon Nebula, the Trifid Nebula, and probably a few others; I didn’t rigorously keep track.

Appropriately, the party didn’t end so much as dissipate. London and I were car-camping–I was doubly happy about that after seeing all the apparently radioactive scorpions cruising around the campground–so when he finally got ready to go down I retreated from the star party scene and set up the Astroscan next to the car for a quick session. I only observed for about an hour, but I cruised through about a dozen of the best and brightest deep sky objects, including the North American Nebula and the Veil Nebula, which I can’t see at all from my side of the mountains. I ended on Jupiter and its moons, which were appropriately stunning.

It was kinda cool to get out with the ‘Scan. The only other time I took it out to a dark site was also a camping trip–back in 2008 I got to take some students from my ecology class camping in Yosemite, and I took the Astroscan along and gave one of the guys his first-ever view of Saturn. It’s a solid little scope. The f/4 light cone is pretty brutal on eyepieces, but it has a crazy wide field and as long as you don’t push the magnification too high, you can have a lot of fun. I have a feeling that scope is going to be seeing more action in the future.

This morning London and I ate a lazy breakfast in camp and took our time getting around. On the drive out we saw a tarantula crossing the highway, so we stopped and watched it for a few minutes. If they gave out medals for doing the spider dance I would have a vault full of trophies, so for me this was an exercise in deliberately creeping myself out. Anything that has more legs than I can easily keep track of is Not Cool in my book. But sometimes even Not Cool is cool. Especially if you and your little boy are scaring yourselves silly watching a humongous spider.

In Yucca Valley we ran into some dinosaurs. Dinosaurs are cool, and roadside dinosaurs are extra cool, but that’s a story I’ll have to take up later this week, over at SV-POW!

Final verdict? I had a fantastic time. At one point when no one else was near him, I got to talk with John Dobson for a few minutes and to tell him how much his brand of sidewalk astronomy had inspired me. He was kind enough to autograph my star atlas; I couldn’t think of a more appropriate thing to bear his signature. The site was dark, the sky was clear, the weather was perfect, and the SCDVA were very generous and entertaining hosts. If you ever get the chance to attend one of their shindigs, do it. Maybe I’ll see you there!

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Guess what? The SkyWatcher 130N-EQ2 is still a pretty good deal

October 2, 2010

As I blogged a few months ago, at the end of this past spring Amazon put a couple of SkyWatcher scopes on closeout, for seriously ridiculous prices. At one point the refractor was going for just $36 shipped, and not surprisingly they sold out of those, apparently permanently. The 5″ reflector, the 130N-EQ2, was going for $100. Amazon still has those, but if you click on the old link, you get taken to a page where they are selling for an unbelievable $399. This is unbelievable because the list price of the scope and its clones is only $269. They’re good scopes, no doubt, but hardly collector’s items, and I just can’t fathom the 30% markup.

ANYWAY, once the scopes on that page went up to darn near $400, interest in them quickly dwindled. But as luck would have it, the 130N-EQ2 is still available on Amazon at a discounted price. This page has them for $150, which is great, but with $44.58 in shipping, which kinda stinks. On the other hand, you still end up with a decent 5″ scope for under $200, which is pretty darned good. Probably the closest thing out there in terms of price and features is the equatorially-mounted version of Orion’s popular StarBlast 4.5, which goes for $219 + $10 shipping.

So how do the two compare? The StarBlast 4.5 has a parabolic primary mirror, whereas the 130N-EQ2 has a spherical mirror, but the StarBlast has a very fast focal ratio of f/4 compared to the SkyWatcher’s more forgiving f/6.9. The spherical mirror of the SkyWatcher means that spherical aberration becomes limiting at high magnification–say, anything over about 200x. On the other hand, StarBlast’s very fast focal ratio means that it will suffer from another aberration, which is coma. In short, the stars toward the edge of the field start to smear out into seagulls instead of nice little points of light. It bothers some people more than others, but the bottom line is that most users (including me) find the StarBlast maxing out between 150x and 200x, whereas in my experience the 130N can be pushed a little higher, to just past 200x, before the image starts to get ugly. So IMHO, the mirrors are pretty much a wash, with the 130N perhaps having a slight advantage.

The 130N-EQ2 has a beefier mount, an EQ2 vs the StarBlast’s EQ1, but it also weighs about three times as much so the heavier mount makes sense. The StarBlast comes with two of Orion’s Expanse series widefield eyepieces, which I and most others consider a step up from the Plossls that come with the 130N. Nothing against Plossls, they’re good, solid workhorse eyepieces, but the wider apparent field of view of the Expanses gets addicting pretty quickly. Both scopes have the same red-dot finder.

On balance, the two scopes look pretty similar on paper, and I think both are good choices for a starter scope or a grab-n-go or travel scope. But of the two, I’d still go with the 130N-EQ2. The slower focal ratio means that collimating (aligning) the mirrors is not quite as tricky as with the StarBlast, and the longer focal length makes it easier to power up on planets and other targets that cry out for high magnification. And the little bit of extra aperture doesn’t hurt–a 130mm scope gathers about 30% more light than a 114mm scope, which will mean the difference between seeing something and not seeing it if you really push the scope to its limit. And it’s about $35 cheaper, at least right at the moment. On the flip side, the StarBlast is quite a bit shorter, quite a bit lighter, and has a wider field of view. So if you’re considering either one, think about what qualities you value most.

Why is all of this on my mind? Last night I  was hanging out with my buddy Andy Farke, and we noticed that after a day of scattered thunderstorms, the sky was remarkably dark and clear. He got out his 130N and 15×70 binoculars and we spent a very pleasant hour just cruising around the sky. We hit just a handful of showpiece objects–the Andromeda galaxy, the Double Cluster, the Pleiades, Jupiter, and the moon–but we spent some time lingering over each one. It has been months since I’ve had observed with a 130N, and I’d forgotten what a good performer it is. Everything we looked at looked darn good. Atmospheric turbulence kept us from pushing the magnification very far, but at 72x Jupiter was showing a lot of detail, with several visible cloud belts in moments of steady seeing. The moon looked downright fantastic–it’s late enough in its cycle to not be overwhelmingly bright, and we spent some time cruising over western features that we don’t often see catching the setting sun (setting on the moon, that is).

One of the guys with us lamented not getting a 130N when they were a hundred bucks, now that they had gone up to four hundred, and that reminded me that these fine scopes can still be had for about half of that. I told him so, and now I’m telling you.

Finally, if you’ve already got a mount, OPT has a 5″ parabolic reflector on clearance for just $70 plus shipping (UPS, you pick the mode and speed). It’s just the optical tube, no eyepieces and nothing to put it on, but if you’ve got a mount and tripod, it would make a great grab-n-go or widefield scope.

That’s all for now. I’m off to the desert tonight for some serious stargazing, so hopefully I’ll have more to report soon. Clear skies!