Sunday, October 31, 2010

 

The Herschel Project Night 14


I should be on my guard when an observing run gets off on the wrong foot. Not that I thought I was putting that wrong foot in it at first. The last new-Moon Saturday looked like it was gonna be a nice one. Dry and cloudless, as dry and cloudless as it’s been down in the swamp in a right smart spell. I gave myself plenty of time to gather up all my stuff in leisurely fashion and position it in the front parlor. Did not get all sweaty and stressed in the process of loading Celeste, my C8, and the CG5 mount in the car. Grabbed a bottle of water, hollered to Miss Dorothy “Honey, I’ll probably be pretty late,” and pointed the car west toward Tanner Williams and the PSAS dark site. What could happen?

As I said not long back, I always forget something. I know that, so I run through the equipment inventory in my head as I’m leaving. If I had half a brain, I’d use the gear checklist I made up a while back, but I yam what I yam, I reckon. About a block from home, I suddenly realized I’d forgot the Astrogizmos red filter I put over the netbook screen. When I’m doing Stellacam deep sky video, as I’d be doing on this night, my night vision doesn’t matter much, but I try to be as considerate as possible regarding spurious light so as not to disturb my fellow PSASites. I turned the car around, grabbed the filter, set out again, and all was well. But I started wondering whether this misstep might be a bad omen.

It occurred to me as I was pulling into the PSAS dark site that the red filters weren’t the only thing I had forgot. The Bahtinov mask I use for fine-tuning focus was sitting back in Chaos Manor South. Not a big hit. I love the (Farpoint) Bahtinov, since it helps ensure my focus is on the money every time, which is important with the Stellacam’s smallish chip, but I’ve focused astro-cameras for years without one, so I figured I’d endeavor to persevere. I did resolve that enough was finally enough. From here on out I go back to using my checklist.

When I was done with my disconsolate and peeved muttering about the Bahtinov mask, I focused a weather eye on the sky. Not bad, not bad at all. There was a little haze, but not much. Way down on the western horizon there were some clouds, but they were skittering off and it was evident it was gonna be a good night. Maybe a real good one. There was also a young, slim Moon in the sky, but she was following Sister Venus into the gloaming, and wouldn’t be a problem.

Everything would likely have gone like clockwork if I hadn’t got ambitious. I would, as last time out, be using my 1995 Ultima C8, Celeste, on my beloved CG5 mount under the control of NexRemote, which takes the place of the NexStar hand controller. NR allows you to select the telescope firmware version you want to use, with version 4.16 being the latest offered for the CG5 GEM in the current build of NexRemote. Not that I normally use 4.16. I’ve stuck with v4.13.

What’s so different about 4.16? Celestron redid the polar alignment routine. The old version points the scope where it assumes Polaris will be given a perfect polar alignment. You then adjust mount altitude and azimuth till the North Star is centered in the eyepiece, which yields a polar alignment more than good enough for the Stellacam’s 10-second exposures.

All-star is, however, superior, or so I’ve been told. In addition to allowing any star—well almost any star—to be used for polar alignment, it is reputedly considerably more accurate than the Polaris routine. I’ve been happy with the old software, but, hey, if that elusive More Better Gooder is available for free, why not take advantage of it? While I’d tried this new software once, briefly, down in Chiefland, I hadn’t really got comfortable with it. Since there would be neither Herschel I nor Herschel II objects available this evening, I figgered this would be the perfect time to give 4.16 another try.

I reviewed the All-Star instructions (which have still not been included in the CG5 manual) one more time as the Sun sank. Didn’t seem too hard. Main difference is that you now access polar alignment from the Align button instead of the Utility Menu. To begin the procedure, you send the scope on a go-to to a named star. This star should, according to Celestron, not be near the eastern or western horizons and should, if possible, be high in the sky near the Local Meridian.

Hmmm…lessee. Well, there was Altair shining his little heart out. He was, if not at culmination, at least near it, and since he’s almost on the Celestial Equator, I figured that qualified as "high in the sky." Despite the All-Star directive to choose a star “high in the sky,” they also caution you to avoid one “directly overhead.” Altair was high, but not right overhead, and I guessed it would be as close as I could get to complying with the somewhat ambiguous instructions.

Once I had Altair in the field and carefully centered, it was time to begin polar alignment by pressing the Align button and scrolling to and selecting “Align Mount.” When I hit Enter, the scope re-slewed to Altair, and following instructions, I centered the luminary in my finder and then in the field of my 12mm reticle eyepiece. So far, so good.

The final step is to press the Align button, which first syncs on the star and then slews the scope to the place it believes the star should be given a perfect polar alignment. Then, just as in the old Polaris alignment procedure, you recenter the star in the main scope using the mount altitude and azimuth adjusters (never the R.A. and declination buttons). That’s when doubt began to creep in. I did not like what I was seeing.

The place the mount slewed to was a good ways from Altair. By Herculean effort, I got it in the field with the alt/az screws. Sure seemed like I was lowering the polar axis a whole lot, though. Wouldn’t have thought that would be necessary, since I’d put Polaris smack in the hollow bore of the polar axis before I began my go-to alignment. Maybe with Altair high in the sky it just seemed as if I were having to move the star a long ways due to my uncomfortable perspective. The NexStar ought to know what it was doing, oughtn’t it?

What next? I’ve been told that if you do the All-Star procedure correctly, there should be no need to re-do your go-to alignment. In line with my usual thinking, though, “trust but verify,” I decided to check the mount on one object before setting up the Stellacam. Off to M13. Nope. Nada. Zip. Zilch.

Hokay. The instructions caution that this can happen, and suggest unsyncing the All-Star star, replacing alignment stars, yadda-yadda-yadda. I just hit the big switch and redid my go-to alignment, adding Calibration Stars until one (the third one) was in the field of the main scope when the slew stopped. Alrighty then, “M13.” There she was near the center of the field. I was good to go with 4.16, right? Hah!

Got the Stellacam II hooked up, SkyTools 3 running, and focused as best I could on M13. Why “as best I could”? It’s a little hard to focus on a moving target. No, the CG5 is not an AP1200, but with the HC polar align procedure done, you get round stars with the video camera’s short exposures. Except I wasn’t getting that. Even if the stars were near-round on a single frame/exposure, I could see something was wrong, since they moved a considerable distance on the screen when the Stellacam’s image was refreshed with the next exposure.

Hmmm… What to do? Well, maybe it was just that I was pointing fairly high in the West to get at M13. Perhaps poor balance was making the CG5 tracking a little less good than it usually is. There is no doubt balance is important with a GEM in this class. But… What I was seeing looked a heck of a lot worse than that. It looked like bad declination drift, an artifact of poor polar alignment. Nevertheless, I pushed on to the first object of the evening. I’d already wasted too much darkness fiddling around with the scope.

Yeah, I decided to just put up with the mis-tracking if I could. After a few objects, I decided I couldn’t. Hell, the progress of stars and DSOs across my monitor was making me dizzy. I’d already wasted a lot of time and didn’t relish wasting more, but it looked like the whole run would be a waste if I didn’t do something. I returned to NexRemote’s settings screen and cycled power on the mount.

At the NR settings display, I used the pull-down menu to choose my software build—one of the beauties of NexRemote. You can bet I didn’t pick 4.16; I went back to the tried and true 4.13. Yeah, it was a pain: do a go-to alignment, complete the old-fashioned Polaris polar alignment routine, and redo the go-to alignment (mandatory with the old software). I’d probably burned close to an hour with little to show for my work. What was done was done, though, and at least now when I sent the scope to M13 it was not only centered, it stayed centered exposure to exposure.

So what was the deal? Was it the software or was it Unk? I’m guessing we all know the answer to that one. All-Star has, from what I can tell, gotten rave reviews from all and sundry. It obviously works at least as well as the old polar alignment utility. Then how did your silly old Uncle screw it up? I don’t know. Altair was a little close to being straight overhead, but I really don’t think that was it. I’ve gone back over the instructions a couple of times and tried to review in my mind what I did. I suspect—suspect—that I messed up the step where you press Align following the mount’s initial re-slew to the star. It is possible I, out of habit, pressed Enter instead of Align. I am not giving up on All-Star, and intend to give it another chance some evening “soon.”

With the mount finally running right, it was time to get to work. At least it was good and dark now, and despite some lingering haze the Milky Way was obvious overhead. Where to begin? SkyTools said no Herschel Is or IIs I need were available, so it was back to the Big Enchilada, the whole list, the Herschel 2500. As in the past, I will not try your patience by describing every cosmic dust bunny I visited in my trek across Aries, Andromeda, Pegasus, and Triangulum, but I will mention a few of the outstanding objects—75 all told—I visited on this run.

As per usual, “POSS” is the Palomar Observatory Sky Survey, galaxy morphological types are where possible given according to the de Vaucoleurs system, matter in italics was transcribed from my log audio recordings, and images (except Hartley 2) are from the POSS. There are a couple of references below to NED. Who or what is “NED”? I’m a-talking about the NASA Extragalactic Database. If you are a galaxy hound, you owe it to yourself to try this wonderful tool. Just about any island universe in the sky is there, and there are reams of data and images for every fuzzy. Best of all? IT’S FREE!

Pegasus was high up and out of the light dome, so to his awesome Great Square I went. I’m just amazed, y’all, at how the summer observing season has flown by. It hardly seems possible the fall constellations are riding high and the winter ones on the rise before a night is out. Sigh. I must be getting old.

Pegasus

NGC 7550 (H.III.181) is set in a lovely little field. The galaxy itself is a magnitude 13.1, 1.5’ x 1.3’ E-S0 elliptical. In addition to it, there is a nice looking barred spiral, NGC 7549 about 5’ to the North; NGC 7558, an elliptical, is a bit less than 6’ to the east; and another barred spiral, NGC 7547 is 3’ to the west. Together, this small galaxy group is known as Hickson 93. Sweet.

A magnitude 14.2, 2.2’ x .6’ edge-on Sbc spiral according to N.E.D., NGC 52 (H.III.183) is right attractive. On its POSS plate, the galaxy shows off a tiny dust lane, and I almost convince myself I’m seeing that with the C8/Stellacam tonight.

NGC 7497 (H.III.303) is at magnitude 13 and subtends 3.4’ x 1.1’. It’s an intermediate inclination Sc. What it looks like to me is a tiny M82. There is some dusty looking detail visible in the POSS image and on my monitor, but I think this “M82 look” comes from the fact that there is a magnitude 15.6 star about 30” southwest of the bright, small nucleus, and the two create a false “dust lane” between them.

NGC 7681 (H.II.242) is a dim one, a magnitude 15.7 S0 lenticular. It’s relatively small, too, 1.5’ x .8’. A double star is 2’20” to the east and there is a faint, magnitude 16 star about 20” to the northeast of the galaxy’s center. Onscreen, the galaxy is a small, slightly elongated bright spot with slight hint of nebulosity around it.

An E type elliptical 1.7’ x .9’ in size, NGC 7647 (H.III.473) shines weakly at magnitude 14.6. With the Stellacam, it is a slightly elongated fuzzball that’s redeemed by the presence of several small galaxies in the immediate area. Collectively, this group is known as Abell 2589, or, to be exact, “ACO 2589” in recognition of the fact that the catalog of galaxy clusters done by George Abell was extended by Conwin and Olowin.

As the night aged, Triangulum began to emerge from its light pollution cocoon, so Celeste and I ventured over to this little constellation’s surprisingly extensive galaxy field…

Triangulum

NGC 750 (H.II.222), a magnitude 12.9 E peculiar galaxy, is weird looking. It’s immediately obvious there are two “lobes” involved. What it looks like is a galaxy with two nuclei. And that’s apparently just what it is. This 1.7’ x 1.3’ object is classified as a “dumbbell galaxy.” Supposedly, the two lobes are the centers of two interacting ellipticals contained in a common stellar envelope. NGC 750 and other dumbbell galaxies are what the N.E.D. refers to as “binary elliptical galaxies.”

After Triangulum, we headed to nearby Aries. Aries? Yep. You mean you didn’t know this small “forgotten” constellation is just chock-full of island universes? Is it ever. There were enough that by the time I got to the end of the Ram’s Herschel riches the night was growing old and the air was growing cold. In other words, it was REBEL YELL TIME.

Before tearing down, I did take a minute or three to have a look at this fall’s little hit of a comet, Hartley 2, as it drifted along not far from the Double Cluster. As you can see in this single-frame Stellacam snapshot, it’s a nice one. Bright little nucleus, some coma, and even hints of a tiny little tail. It was almost as outstanding visually through my buddy Jason’s NexStar 11. Be sure to get out and have a look at it this coming week, y’all. Sky and Telescope’s website has finder charts and other cool Hartley stuff for your perusal.

Takeaway this time? Obviously, I've still got some work to do with All-Star. No, I don’t really need to use it, but now it’s an ISSUE with me and I won’t be happy till it is conquered. Otherwise? I am continually amazed at how downright powerful my C8 and CG5 and Stellacam are. It’s often said a Stellacam (or Mallincam) can effectively triple the aperture of a telescope, but what I’ve learned while going through the Herschel 2500 is that the video advantage is considerably greater than that. I’ve seen detail in small, dim galaxies from our less than pristine skies the likes of which I have never seen visually in a 24-inch telescope.

Not that I eschew the visual. That is still a big part of the Herschel Project and will continue to be so. I hope to get out to the PSAS darksite this coming weekend with my 12-inch Dob, Old Betsy, and get her tuned up and ready to go for the Deep South Regional Star Gaze, which will be four nights of visual Herschel heaven.

SkyWeek from Sky and Telescope

Psst, buddy! Got 99 cents? Got an Apple handheld—an iPhone, iPod (Touch), or iPad? If the answers are “yes,” man do I have an astronomy program for you! The good folk at Sky and Telescope have just released their first app, SkyWeek. What it is is a little program that connects to the Internet and downloads all the information you need to know about the week’s observing events. It’s like the “Observing” pages from the Sky website, but better, since you can carry it around with you.

What do I like about it? There’re beautiful star charts and glitzy things like an animated Lunar phases screen and cool graphics of Jupiter’s Great Red Spot and Moons you can step forward and back in time. Best of all, it’s easy for computer ignorant old Unk to work. Just download it from the app store using either a PC and iTunes or the handheld, and tap the purty little icon. As long as you’ve got location services turned on in your device, SkyWeek sets date, time and location for you and all you have to do is enjoy.

Given that my memory ain’t what it used to be—if’n it ever was—SkyWeek will go a long way toward seeing I don’t forget upcoming astronomy events. Now, if the Sky and ‘Scope folks could just develop an app to help me remember to bring my eyepiece case along when I go observing, I’d really be in business. If you’re an Apple user, don’t ruminate on it; just get this 99 cent wonder. You’ll thank me later, muchachos.

Sunday, October 24, 2010

 

Public Outreach with Ben Weaver


Every astronomy club I’ve belonged to has had at least one Ben Weaver. You know, the mean old man from The Andy Griffith Show who always wants Ang to throw the poor mice of Mayberry in jail on Christmas Eve for jaywalking. Doesn’t like kids—oh, no. And if he’d been an amateur astronomer I’m pretty sure he wouldn’t have liked public outreach. Why not? The reasons I hear from our Ben Weaver wannabes are these, the official Astronomy Curmudgeon Top Ten:

"You say this is the way we recruit new amateur astronomers? I don’t want any more amateur astronomers. The club observing field is too crowded now!"

"It’s too much trouble to organize dadgummed public star parties."

"We don’t have anywhere to hold a public star party."

"The place where the club is having the public outreach stuff is too light polluted, and there’s gonna be a fat moon in the sky on the date the idiots have chosen!"

"The kids ask too many questions."

"It’s too boring."

"I’m too busy."

"Those nasty tykes with their lollipop-sticky hands and teenagers with caked-on makeup will ruin my expensive eyepieces."

"Today’s kids are out of control. First thing that’ll happen is one will run helter-skelter into my beautiful AP refractor."

"They won’t be interested anyway; they hate science. All they like is them consarned video games."

OK, Mr. Weaver…let’s deal with your objections one by one:

You say this is the way we recruit new amateur astronomers? I don’t want any more amateur astronomers. The club observing field is too crowded as it is. I’ve yet to be a member of a club where the observing field—or even the monthly business meeting—was “crowded.” But even if yours is, there are still reasons to bring new amateurs into the fold.

Look around at the next meeting. Are your colleagues’ heads as gray as yours and mine? I don’t know about you, but I’d like to see my club continue on down the decades of this new century. My desire for new blood ain’t all altruistic, either. It will be nice for me and my fellow officers to finally turn the work of running the club over to a new generation of amateur astronomers. One curious thing? Many of the folks who look down on public outreach are often the same ones pontificating about “the graying of amateur astronomy.”

None of that strikes a chord? Well, you like gear don’t you? Plenty of new telescopes, and eyepieces, and widgets of every description to drool over and sometimes buy? Imagine how much more of that there would be if we had twice as many amateurs as we do now.

It’s too much trouble to organize dadgummed public star parties. Getting one together can be a lot of work—but only if you let it. Most of the time you and your buddies won’t have to do any organizing work at all. You can do as we do and hold your star parties in conjunction with the local school system or a similar outfit. They handle the venue and the publicity and all we have to do is show up with our telescopes.

We don’t have anywhere to hold a public star party. As above, you let somebody else find a spot for you. That is, you set up on the grounds of your sponsoring organization: in the schoolyard, the back forty of the children’s science museum, the parking lot of the church, whatever.

The place where the club is having the public outreach stuff is too light polluted and there’s gonna be a fat moon in the sky on the date the idiots have picked! Yes, the elementary school playground is probably ringed with sodium vapor streetlights. But so what? It really doesn’t matter. The public, kids and adults, don’t care pea-turkey about looking at NGC 7817, your favorite 12th magnitude galaxy. They want to see the Moon, a planet, and maybe a bright star or two. The combination of the public and lots of telescopes is one that goes better with a little ambient light, anyway. You don’t want little Suzie braining herself on the pier of your AP1200 GEM, do you? Don’t answer that, Ben!

The kids ask too many questions. They do ask a lot of questions; that’s what little folk do. My years of doing public outreach and teaching astronomy to college freshmen have taught me that not only are they full of questions, but that youngsters have a sixth sense for asking the very ones you don’t know the answers to: “But how big is Callisto, mister, how big, huh?”

The solution? If you don’t want to embarrass yourself in front of a horde of six-year-olds, decide in advance which objects you will show, and bone up on them. It is not going too far to suggest you put some facts and figures on note cards. If you have a go-to scope, the hand control probably has plenty of information about whichever object you are sitting on, and the small folk will enjoy reading (or listening to you read) the facts of the matter off the little computer.

It’s too boring. I have never, ever found teaching astronomy to kids to be boring. They are always full of surprises, and most often I mean that in a good way. There is nothing at all boring about their looks of wonder when they see the marvels of the night sky through a telescope, your telescope, for the first time.

I’m too busy. I’m busy. You’re busy. We’re all busy. You mean to tell me you can’t get ONE NIGHT OFF from whatever you do to bring astronomy to your community? You don’t seem to have any trouble taking off a couple of weeks every summer and heading to the Texas Star Party. It could be argued that showing the public the sky is, in the larger scheme of things, more important than you doing the TSP Crazy - Hard Object List every single year.

Those nasty kids with their lollipop-sticky hands and teenagers with caked-on makeup will ruin my expensive eyepieces. I’ll admit I wouldn’t want the eyelens of my 13mm Ethos coated with teeny-bopper mascara, either; even if no permanent damage were done. But that’s no excuse for not getting out there with the public. If you’ve been in the game for a while, you undoubtedly have a drawer full of inexpensive Kellners and Plossls that will perform more than adequately. Worried about your scope, too? If you don’t have a second and less fancy instrument, it’s inexpensive to pick-up a used rig for use with the kids. They will be just as happy with a 6-inch Orion Dob as they would be with your prized AP 150 caviar-refractor.

Today’s kids are out of control. First thing that happens is one will be running helter-skelter and will knock over my telescope. Translation: YOU KIDS GET OFFA MY LAWN! As we get older, it’s tempting to blame the younger generation for all the things we perceive as wrong about our culture. Our parents did it…theirs did…and on and on.

What we are really feeling is the melancholy that comes with knowing that the torch is being passed to the next generation(s), and that we are no longer the end-all and be-all of existence. That’s particularly difficult to face for us spoiled baby-boomers. Most kids are well behaved; it’s usually the parents that cause problems.

They won’t be interested, anyway, they hate science. All they like is them consarned video games. The ground truth? Kids are a little different today. They grow up in families different from what you remember from Leave it to Beaver (actually, the Cleavers hardly represented the average 50s family). But they are smart. At least as smart as we were, if not smarter. And I see one thing semester after semester: computer games or no computer games, kids are still interested in the Great Out There. They don’t have a manned space program (much of one, anyway) to light the fire as we did, but they are every bit as excited about getting a look through a telescope as we were.

Still skeptical, Ben? The idea of showing the stars to 300 kids is still—admit it—a scary one? No need to be afeared. Let me take you through a typical public star party run, one me and my mates in the PSAS, the Possum Swamp Astronomical Society, did a couple of weeks back.

Not only do we hold our star parties in cooperation with the local school system, we’ve been lucky enough to be able to hold them at the same, excellent public school venue for over two decades. It’s no secret to anyone inside or outside the state of Alabama that education is strapped for money here. It always has been, with public schools never having been the highest priority for our politicians. Nevertheless, the county schools down here in Possum Swamp have, by Herculean effort, managed to build and hold onto an Environmental Studies Center in the suburbs. Oh, the (elected) schoolboard has tried to shut this “frill” down a time or two, but the Center, its dedicated staff, and we--the PSAS--are still here.

Honestly, I can’t think of a better place to hold a public star party. While the “ESC” is now in the midst of plenty of suburban street lights, the lighting on the beautiful, park-like grounds is sparse and sensible, so ambient light is not a problem. It’s certainly worth putting up with the general light pollution to have a modern classroom/laboratory building at hand (with its all important bathrooms and coke machines). Having the ESC folks available to handle all the logistics is another huge plus. Most of all, though, every adult Possum Swamp native has visited the ESC during their schooldays, so it’s a warm and friendly place they are eager to return to with their kids.

To misquote Forest Gump, “Public star parties are like a box of chocolates; you never know how many kids will show up.” I expected a largish crowd this time, since conditions were just about perfect. Dead clear skies, a nice crescent Moon, Jupiter on the rise, and temperatures in the 50s. Only thing that might tend to keep the numbers down was that we’d had to schedule the event for the beginning rather than the end of a semester, so we wouldn’t get the kids desperate for the EXTRA CREDIT the science teachers give for attending an “ESC Sky Watch.”

Telescope? As I have said before, I believe simpler is usually better—up to a point. I leave the go-to rigs at home. Thing is, as soon as the Sun is down—or even before—your “customers” will begin to arrive and will want a look at the Moon right away. Some go-to scopes can skip alignment or be aligned well enough on the Moon so they at least track, but what’s the point of having a go-to rig if you do that?

How useful will go-to be, anyway, even if you do have time to get the mount properly aligned? You ain’t gonna be hunting 14th magnitude galaxies on a public night. A computer scope is also more time-consuming to set up and is festooned with cords, buttons, and switches that may prove irresistible for little fingers.

How about a Dobsonian? I’ve used Dobs at public outreach events, but have never felt they provide a good experience for the lollipop brigade or for me. I spend too much time re-centering objects between observers, and a Dobsonian is way too easy to move off target by the small, eager hands that will inevitably clutch the focuser despite my pleas of “Look, don’t touch!” A really big Dob? Fuhgeddaboutit. Do you want seven-year-olds climbing your orchard ladder in the dark?

My scope of choice? My trusty RV-6 Criterion Dynascope Newtonian, Cindy Lou. This 40 year old trouper has everything you need for a public star party: excellent optics, a clock drive, and an interesting appearance. I do have to provide a stepstool for the wee-est of the wee to reach the eyepiece, but that is not a big problem. Usually, thanks to the scope’s tube rings, I can position the eyepiece so most of my young observers can observe flatfooted on the ground.

It’s not just ergonomics, either. Point an old Dynascope or other Newtonian refugee from the 1960s at the Moon, and not only will your audience be gobsmacked, you will be too if you’ve forgotten what a beautiful job these antiques can do. Don’t have one? They, and especially the Dynascope RV-6es, are often no farther away than a local Craigslist ad, where they can usually be had for a song.

First thing I noted after I’d got the RV-6 out of the car and set up? The ESC had finally got around to tearing down the PSAS’ old roll-off-roof observatory. In truth, it was time. Our little observatory was pretty dilapidated after enduring two decades of Gulf Coast summers. We’d kept it painted and in repair for many years, but lately? Not so much.

We’d originally intended to use it for public outreach with our 12-inch Cave Newtonian, but that never worked out. Kids had to climb a ladder to reach the eyepiece and, as with a bigdob, you don’t really want them doing that. Also, most members wanted to use their own scopes at public nights rather than open the observatory, sweep the spider webs away, get the humongous 12-inch going, etc. I have preserved the big Cave GEM mount for possible future use—a tornado strike on the ESC did-in the OTA some years ago, alas.

Hokay, status check. We had six telescopes set up and ready to go. I figured that might be barely enough. The last thing you want is too-long lines, though short ones actually seem to increase excitement and anticipation. If we were deluged with kids, I had Anita, the ESC’s newest and very enthusiastic teacher and also a brand-new PSAS member, standing-by with an old Meade white-tube Dobbie.

By the time the Sun was down, I had the RV-6 on Luna, she was delivering an absolutely beautiful image, and a line was forming at my scope. Not because the ESC staff had herded the kids and parents into a line; they organized themselves. Our customers were polite and well-behaved, and that has been the norm over the years. The only times things have gotten dicey in that regard have been when we were completely overwhelmed during special events—Lunar eclipses and Comet Hale Bopp. In those cases, the fault was ours. You simply cannot handle crowds approaching 1000 comet-crazy civilians with ten telescopes; we should have been better prepared.

My targets? I stayed on the Moon most of the time, since that, again, is what the kids and their elders most want to see. I did shift over to Jupiter for a while, though. The seeing wasn’t good enough to allow Jove to really strut his stuff, but our guests didn’t much care. They were enchanted by the Galilean moons (one tot, not surprisingly, asked me which moon was the biggest and how big that was, but I was PREPARED) and by “Jupiter’s ring” (the NEB).

I suppose it would be nice to have every telescope on the field on a different object, but in light pollution with a Moon in the sky, you really are restricted to the “biggies”: planets, Moon, a bright star (Vega this evening). Having the scopes at distinctly different magnifications seems to satisfy our patrons’ desires for “different at each telescope.”

As the evening began to wind down and the youngest observers were trundled off to bed, I did aim at a couple of deep sky objects, M13 and M57—if for no other reason than to prove to myself that I can still star hop with a small finder in a light polluted sky. The RV-6 did a very nice job on both the Great Cluster and the Ring, but, predictably, the response from the kids was ho-hum, “Can’t we look at the Moon some more?”

By 8pm, I was on the road back to the Old Manse with the RV-6 and sure didn’t feel like I’d foolishly sacrificed my evening on the altar of public outreach. I’d had a good time, as always. Would I like to do once-a-month public star parties? I don’t know about that, but twice a year is simply not a huge imposition, and I believe, frankly, that we’ve done some good for kids and for amateur astronomy over the last twenty years.

So there you have it, Mr. Weaver. Wasn’t so scary was it? No scopes were trashed. Plenty of excited kids looked at the Moon and Jupiter. One day, as you (and me) run aground on the shoals of old age, you may even find yourself looking through the giant computer-festooned telescopes of kids who got their start as amateurs on this night.

Thinking back to those old Andy Griffiths, by the end mean old Ben Weaver always showed he really had a Heart of Gold. It’s been this old boy’s experience, muchachos, that at the end of a public outing most astronomer-curmudgeons can’t stop talking about the look on that six-year-old girl’s face when she saw the craters of the Moon for the very first time.

Sunday, October 17, 2010

 

The Herschel Project Night 13


Who says thirteen is an unlucky number? Night thirteen of the vaunted Herschel Project turned out to be right lucky for your old Uncle. Not that there weren’t a few black cats and walked-under ladders along the way. Seems like with Unk there is always something; every observing run is an adventure.

The evening started gamely enough. For once, there was absolutely no doubt the weather would cooperate. Not only were the skies dead clear, it was obvious they would stay that way. Wunderground.com predicted Saturday evening to be cloudless and was prognosticating the same thing for the whole of the next week. Just when it seemed as if fall would never arrive on the Gulf Coast, here it was.

Course, that means we begin to lose what I consider the perfect temperature forecast for long observing runs, “mid sixties.” By the time I arrived at our dark site, an airstrip that’s unused at night, there was a chill in the air. That was OK; for once, I’d had the good sense to listen to Miss Dorothy, and at her urging had brought along an honest-to-god coat, not the fleece I’d started out the door with.

Speaking of Miss D., those of y’all who’ve given us your support and kept us in your thoughts through her battle with cancer will be pleased to hear she is very much on the mend. She is still weak as a kitten, and has a ways to go yet, but is feeling more and more like her old, wonderful self with each passing day.

Anyhoo, the first thing I did, as I always do, was kick on the Thermacell mosquito repeller. It’s certainly gotten plenty of use this humid, buggy summer, and I’ve probably helped Bass Pro’s bottom line with my frequent trips there for refills. On this night, the skeeters were blessedly light, and my magic bug zapper easily kept the few refugees at bay. Only when I wandered over to a fellow club member’s setup at the opposite end of the field was I assaulted by buzzing biters. Frankly, I don’t know how I got along without a Thermacell. I will never, ever go back to slathering on the nasty, yucky DEET.

It wasn’t surprising, given the beautiful weather, that I had plenty of company for this run, with at least five scopes set up on the field in addition to mine. I like that, though. I enjoy the quiet solitude of just me and one or two buddies, but it’s a nice change to have a night more like a mini-star party once in a while.

Setup of my gear went smoothly at first. I need to get my 12-inch Dobsonian, Old Betsy, out of mothballs soon for a shakedown cruise in preparation for the visual observing I will do over the course of the fall star party season. Tonight, though? Nah. I am getting a little behind on the Herschels—my output has fallen, anyway—and the way to catch up is with my C8, Celeste, and the Stellacam II. The mount? This time I was back to my faithful CG5, who just delivers. She sure did that on this run—once I finally got going, that is.

Yes, setup went smoothly—till I was putting the finishing touches on the rig. I’d got the OTA on the mount, all the cables hooked up, and the DewBuster and its heater strips connected to my jumpstart battery and ready to go. All that remained was to mount my f/3.3 reducer on the rear port, screw a visual back on that, and insert my Stellacam into the back via its 1.25-inch nosepiece.

That was when the axe fell. I didn’t even have to look in the dry box that contains my accessories. I knew I’d forgot something. An important something. Yeah, yeah, I know. I always forget something, but usually it’s not anything critical (well there was that time I left the NexStar 11’s hand control at home, but it turned out cloudy that night anyway). This, unfortunately, was on the critical side. I’d had the C8’s visual back out of the box while I was working with the Hotech CT Collimator. Clear as a bell, I could see the consarned thing sitting on the dining room table. How in the hell would I connect Stellacam to scope without it?

I thought for a minute. Didn’t I have a T-adapter with me? And a T to C T-ring for the Stellacam? That would work. Screw the T-adaptor onto the reducer and the camera onto that via the T-ring. The only thing that bothered me was that, given the presence of the 3.3 reducer, the camera would be right on the hairy edge of coming to focus.

With the sky assuming that purplish shade it does on good nights, and plenty of bright stars visible, it was time to get aligned. Like always, I was using NexRemote running on my little netbook PC. As I use it, NexRemote takes the place of the NexStar hand control, with the computer connecting directly to the mount’s PC port (on Celestron’s port expander module). NexRemote works fantastically well, and there is nothing sweeter than using a Logitech Wireless Wingman gamepad as my “HC.” After having used a joystick to move the scope, I hate to go back to the stinky little buttons of the “real” hand control.

NexRemote, in her Microsoft Mary voice, announced she was “acquiring” the first alignment star, Arcturus. When she stopped, that huge sun was visible on the screen of the portable DVD player I use as my monitor as the prototypal big SCT donut of an unfocused star. I mashed the appropriate button on my JMI motofocus hand control and the donut began to get smaller and smaller…almost there…almost there…until it reached the size of a nickel on my screen and refused to get any smaller than that.

Was I sunk? Probably. Without the all-important visual back, I couldn’t even switch to eyepieces. I usually have a 2-inch SCT style diagonal on hand, a diagonal with an integral visual back, but I’d taken that out of the gear box, too, and set it aside for some foolish reason. Hey! Wait a minute. Maybe I did have a visual back with me.

I rummaged through my case for a moment and retrieved my nice William Optics 2-inch visual back. A little more hunting turned up a WO 1.25-inch to 2-inch adapter. I removed the T adapter from the scope and the T ring from the camera, screwed the big visual back onto the reducer, inserted the 1.25-inch adapter into the back, and the Stellacam II into that via its 1.25-inch nosepiece.

Arcturus was still far from focus, but pushing the appropriate motofocus button soon had the sparkler good and sharp. In fact, all the stars across the field looked very good, better than they do with my usual setup. Maybe the 2-inch adapter places the camera at a more optimum position behind the reducer than the 1.25-inch back does. Not that my focus didn't need a little fine tuning. I placed my Bahtinov mask over the corrector, tweaked focus by watching the diffraction spikes the mask generates, and was then almost ready to get to work.

The rest was pretty darned anticlimactic. I did a two star alignment, added calibration stars till one of ‘em was on the screen and near the center when the slew stopped, and proceeded to polar alignment. Which doesn’t mean I used Celestron’s fancy new All-star polar alignment procedure. I still need to get friendly with that software, and I am used to and comfortable with The Old Way.

Some CG5 users like the (optional) polar alignment borescope. I’ve never felt like fiddling with that consarned thing, and gave mine to a buddy who wanted it. For my money, the polar align routine built into the hand control (or NexRemote) software is more accurate. It’s easier to use, too: the scope slews to where it thinks Polaris should be given a perfect Polar alignment, you adjust mount altitude and azimuth to center Polaris in the scope, and you are aligned.

I am told All-star is more accurate than the old procedure and doesn’t require you to redo your go-to alignment as the earlier routine does, so maybe I will give it a try next time out. The Polaris align is more than sufficient to yield round stars in the Stellacam video almost all the time, though.

All my fooling around done (I hoped), it was time to get the run underway. Go-tos were outstanding all night long. They were maybe not as good as they could have been, however, since in all the flailing around about the visual back, I’d plumb forgot about the dagnabbed UP AND RIGHT rule.

What’s they-at? All mounts have some backlash. Particularly inexpensive Chinese mounts such as your cheapskate old Uncle favors. For go-to to be accurate, the computer must know about this backlash. Meade accomplishes that by having you do “drive training” with the Autostar hand control every once in a while. Celestron does the same thing by having you do final centering of alignment stars using only the up and right buttons, or, in the case of my joystick, only the up and right positions.

Luckily for silly old me, the go-to system as implemented on the CG5 is pretty derned robust. Despite my faux pas, almost every object I requested was somewhere on the tiny Stellacam II chip. The few that weren’t, some far southern objects, were just barely off the edge, and that was not a problem once I knew which direction I needed to nudge the scope to bring them into view. I accomplished that by going to one of my fave summer objects, splendiferous globular cluster M22. It wasn’t on screen, but was easy to find with just a little slewing around. Informed as to how to bring any off-the-edge objects home, I hit the Herschels.

How did I hit them? With the aid of my favo-right astronomy program, SkyTools 3. A quick check of ST3’s Herschel II list showed I’d once again missed the little Virgo galaxy I still need. By the time I finished fiddle-farting around, it was slap gone. It would be the Herschel I’s to start with, then. Virgo was gone, yeah, but when I looked up, the summer Milky Way was burning with a vengeance straight overhead. There’d be no shortage of objects tonight.

By the way, I am still manually punching object numbers into NexRemote rather than sending the scope on go-tos via SkyTools 3 with NexRemote’s “virtual port” feature. I tried that once with my NexStar 11, the last time I was at Chiefland, and the scope started acting screwy. I suppose I should try the virtual port setup with the CG5, but I’d already wasted a lot of time this evening and punching the numbers into NR is not a big deal.

As always, “POSS” is the Palomar Observatory Sky Survey, galaxy morphological types are where possible given according to the de Vaucoleurs system, matter in italics was transcribed from my log audio recordings, and the images here are from the POSS since I'm too lazy to process my video pix into stills, yadda-yadda-yadda.

Boötes

First object of the night is a galaxy in Boötes, NGC 5676 (H.I.189), a magnitude 12.3 SAbc spiral. It is actually rather impressive; it is large at 4.0’ x 1.0’, is possessed of a bright central region, and shows some hints of arm detail.

NGC 5689 (H.I.188) is also bright. It’s a magnitude 12.8, 3.5’ x 1.0’ long edge-on SB0, a lenticular galaxy. It displays a bright elongated core and a thin disk, which on the POSS plate looks slightly warped.

Magnitude 12.2 NGC 5557 (H.I.99) is 1.9’ x 1.5 in extent, so it is quite bright. Not much to see in this E1 elliptical, though; just a round blob surrounded by a little haze. Bright center, with a dim and small outer envelope. A magnitude 10 star is 5’ to the north.

Ophiuchus

NGC 6426 (H.II.587), a globular star cluster, is much dimmer-looking than I expected. Had to crank up the Stellacam II’s gain to see much of anything. It’s a loose Shapley – Sawyer Class IX. Considerable resolution when seeing, which is not overly outstanding, cooperates. Magnitude 10.9, 4.2’.

NGC 6517 (H.II.199) is another unprepossessing globular. It’s far more compact 6426, with a Shapley Sawyer class of IV, but it’s small, 4.2’ across and relatively dim at magnitude 10.9. No wonder I didn’t see it visually last time under poor conditions with it near the horizon. A few stars are resolved on my monitor tonight.

In contrast to the two previous globs, NGC 6356 (H.I.48) is quite a treat. Magnitude 8.2 and large, 10’. Lovely, with many tiny stars shown.

NGC 6342 (H.I.149), a magnitude 9.5 globular, is another small, subdued example of the breed. Some resolution evident, however, in this class IV cluster.

NGC 6235 (H.II.584), a class X glob, would be easy to miss at magnitude 8.9 and 5’ in size. It is quite loose. There are a few stars scattered across its face, though it’s hard to tell whether all of them belong to the cluster or are part of the rich star field around it.

A large, 20’ across open cluster, NGC 6633 (H.VIII.72) is pretty enough, but with the Stellacam II and C8, even at f/3.3, I really don’t have enough field to set off this rich group.

Scutum

NGC 6664 (H.VIII.12) is a somewhat dim magnitude 8.9 open cluster. It is also reasonably compact, 12’ in size, and rich. Unfortunately, it’s set in an already rich field and is not well detached from the starry background.

Serpens

On its POSS plate, NGC 6118 (H.II.402) is an impressive magnitude 12.4, 4.6’ x 2.0’ multi-armed SAcd galaxy. With my little C8, it’s still nice, with a bright core and fairly extensive and elongated oval outer envelope. There are only the barest hints of its many-armed nature, however.

Cygnus

NGC 6946 (H.IV.76) is a beautiful, face-on SABcd spiral with its arms wonderfully evident on the monitor. This majestic galaxy looks like a blend of M101 and M83. Magnitude 9.6 and 11.5’ along its major axis. In a wide field telescope the nearby rich open cluster, NGC 6939, is visible in the same field as the galaxy, an unforgettable sight!

Ursa Minor

Yes, there are deep sky objects in Ursa Minor, even if nobody (well hardly anybody) ever looks at them. NGC 6217 (H.I.280) is a nice barred spiral, a near face-on SBbc. On my monitor, it has the appearance of what I call a “Tie-Fighter” galaxy; its bar and “solar panels” make it look as if Darth Vader might be at the controls. Magnitude 11.7 and 3.0’ x 2.5’ in size.

Draco

NGC 3147 (H.I.79) is a round, magnitude 11.4, 3.9’ x 3.5’ SAbc galaxy that, on its POSS plate, looks a lot like M94, the Croc’s Eye Galaxy. On my monitor, it’s a bright core with some fuzz surrounding it.

NGC 6543 (H.IV.37), the famous (from its Hubble portrait) Cat’s Eye Nebula, is bright and elongated. Due to its relatively small size, however, 22”, there is not a whole lot of detail visible at this focal length. Some signs of interior detail/annular form. The C8/Stellacam do at least show a little more detail in this planetary nebula than is visible on the POSS plate, where it is completely burned out.

Draco’s NGC 5982 (H.II.764) is a nice little round spot of an E3 elliptical galaxy. Magnitude 12.1, strongly elongated with 2.2’ x 1.3’ dimensions. What makes it cool is that it is sandwiched between two other galaxies. NGC 5985, a magnitude 11.9 intermediate inclination oval spiral, is just 7’26” to the east, and NGC 5981, a cute little magnitude 13.9 edge-on, is about the same distance to the west.

The Splinter Galaxy, NGC 5907 (H.II.759), is amazing tonight. Easily extends a third of the way across the monitor. This skinny, magnitude 11.1, 12.8’ long SAc edge-on features a dark dust lane that’s easily visible with my deep sky video camera.

NGC 5866 (H.I.215) is sometimes referred to as M102. Whether you think it is that, or whether 102 was just a duplicate observation of 101, this S0 is a nice object. It’s a magnitude 10.7, 4.7’ x 1.9’ edge-on lenticular and shows the flying saucer shape of bright galaxies of that type.

With that, I’d exhausted all the Herschel Is that would be available till the wee hours. What next? This beautiful evening seemed like a good time to attack the Big Enchilada, the entire Herschel 2500, the BIG LIST. So I set to work on that with a will, doing all of Andromeda’s objects and many of Pegasus’ multitudinous galaxies. I won’t bore you with endless descriptions of uber-faint fuzzies, but I would like to bend your ear about a couple of outstanding sights:

NGC 523 (H.III.170-2) is all by itself in its field, but is very interesting anyway. This compact peculiar galaxy is obviously interacting with something; there’s a bright bar and considerable off-center haze. There may even be more than one galaxy here.

NGC 68 (H.V.16) is a member of the impressive Y-shaped galaxy cluster Arp 113. Most of them, like this magnitude 14.1, 1.3’ x 1.2’ SA0 dust bunny are just round smudges with brighter cores, but what a view!

NGC 7741 (H.II.208) is a beautiful, classic barred spiral, a magnitude 11.8 Sbc that's 3.8’ x 2.5’. Its two winding arms are prominent with the C8 and Stellacam II, maybe even moreso than on the POSS.

One of the best views tonight, NGC 7339 (H.II.234), an edge-on magnitude 13.1 SAB (s) bc spiral, is paired with the brighter and more well-known edge-on, NGC 7332, which is nearly perpendicular to 7339 and 5’ to the west. An unforgettable sight. Which caused me to holler “SUUWWEEEET!” alarming my fellow observers.

And so it went, till the temperature sank way down into the forties (yeah, that is WAY DOWN for the likes of us), my batteries began to poop out, and a shot of Yell and a warm bed began to beckon strongly. The night had begun with alarms and excursions, but it turned out fine, just fine, in the end, with me having bagged a grand total of 18 objects from the Herschel I and 46 from the Herschel 2500. Not an all-time high-score, but decent, nevertheless.

Next Time: I can hardly believe it, but I got in another wonderful night with the C8/Stellacam the following weekend, crossing many more Herschels off the Big List. I also did some fussing, feuding, and fighting with Celestron’s new 4.16 GEM software, and you’ll get to hear all about that.

Farther in the immediate future? We’ve got our big fall public outreach coming right up. And I’ll be getting Old Betsy tuned up for the next running of our favorite star party, the Deep South Regional Star Gaze, the first week of November. After that, it’ll be me and Miss D’s annual stay at the Hotel Monteleone in New Orleans. Then I hope to get down to Chiefland for a few days, and segue from there into the holiday season. Sounds like “fun” and “busy;” stay tuned, muchachos.

Saturday, October 09, 2010

 

SCT Collimation the New-fangled Way


Hardly seems possible it’s been eleven frackin’ years since I started my SCT-User Yahoogroup. I’ve had a lot of fun with it, and it’s still quite active, though time seems to be passing the good, old Yahoogroups by in favor of glitzier venues. I will admit SCT-User has occasionally been a lot of work, but I knew that going in. Knowing that it would be real work, why did your lazy old Unk start SCT-User in the first place?

Two reasons. First of all, the mother SCT list, the ancestor of all SCT mailing lists, CelestronUser, was dying. I’m not sure why it was giving up the ghost just as Internet astronomy was taking off. Maybe because it was a Major Domo list—referring to the mailing list software running on a university server. It was far from friendly for either users or administrators, and with the new eGroups web-based mailing list system (which would eventually become Yahoogroups) being much more friendly and full-featured, it was no surprise text-based Internet discussion was gravitating to this More Better Gooder.

With CelestronUser going down the virtual tubes, I thought it appropriate to start a new list on eGroups. I was gonna name it Celestron User, just like its antecedent, but just I was about to click the “go” button, I hesitated. Why not appeal to all SCT users, not just Celestron fanatics? Thus was SCT-User born, and long may she wave.

The other reason? I was gobsmacked that in 1999, nearly thirty years after the popularly priced Schmidt Cassegrain hit the streets in the form of the Orange Tube C8, plenty of SCT owners still weren’t able to correctly collimate their telescopes. Some didn’t collimate at all. Worse, most of ‘em didn’t understand why proper collimation is so important with these scopes. Many of these people attributed the poor performance of their telescopes to BAD OLD SCT OPTICS instead of pilot error, their failure to properly collimate or collimate at all. SCT User’s prime directive in the early days was getting the word out on the hows and whys of collimation.

I think we got the job done, spreading the word first to online SCT Users, and then out to our clubs. What did we preach? That collimation ain’t hard. That it’s, in fact, easier to do on an SCT than on a Newtonian (the SCT has only one user adjustable element; the Newt has two). Even more than how easy it is, we tried to impress on users how important it is. Given the SCT’s 5x magnifying secondary mirror, that’s not surprising. The tiniest alignment errors are magnified. Good collimation makes the difference between excellent optical performance and poor optical performance; especially on the planets.

Coincident with our crusade, a small SCT collimation cottage industry sprang up. Most significantly, a man named Bob started selling a collimation aid for Schmidt Cassegrains. Bob’s idea was an humble one for a simple product, but one that was sorely needed. The only puzzle is why it took till the 90s for somebody to begin selling it. What “it”?

Why, KNOBS, Bob’s Knobs. Nobody ever much liked using Allen wrenches to collimate SCT secondaries. Bob’s Knobs provided a much simpler no-tools path to collimation, and when Celestron in their “wisdom”—NOT—changed to Phillips screws for secondary adjustment, the Knobs really took off. I mean, who wants to bring the sharp tip of a screwdriver anywhere near their beautiful corrector? Especially in the dark.

Yep, Bob’s Knobs saved the day. They are simple, yeah, just knurled knob-headed screws that replace Celestron Phillips screws or Meade Allen screws, but they make collimation, if not always fun, at least easy and safe. Bob wasn’t the only person thinking about SCT collimation accessories, however. Some folks were staring at the elephant in the front parlor: why couldn’t SCT users collimate with a laser just like Newtonian users were now doing?

Why would we want to do such a thing anyway? We were now happily tweaking our telescopes to perfection with Bob’s Knobs, after all. Because we were jealous of what the Newt troops could do with their handy-dandy laser collimators. Not only did they, unlike we, not need a star, real or artificial, for collimation, they could make their adjustments in the daytime. In the cotton-picking dining room if’n they wanted to. Dang.

This was during the years of the go-go astronomy marketplace about a decade back, so it’s not surprising several firms picked up on SCT owners’ laser lust. The most famous of these outfits was Kendrick Astro Instruments, who were well known and respected as the folks who commercialized (if not invented) the dew heaters we all use today. When they came out with an SCT laser, I was excited. Given the company’s reputation, surely it would be just what we were hoping for. Unfortunately, doing an SCT laser collimator was a tall order, and Jim Kendrick and company came up just a little short in this old boy’s opinion.

What made it hard to do an SCT laser? Why can’t you just use a pea-picking Newtonian model? Because the modern SCT has only one user adjustable element, the secondary mirror. For a standard laser collimator to work, ever’thing else—the primary mirror, the baffle tube, the rear port, the visual back—has to be precisely aligned and has to stay that way. Which isn’t often the case, but which doesn’t matter for visual collimation.

It really wouldn’t make any difference if our scopes still had primary mirror adjustments, anyway, since a standard laser inserted in the visual back only reflects off one element, the secondary. If the primary is slightly out of whack, the laser won’t “know” about it. Laser collimation in this fashion is a recipe for SCT MIScollimation.

So how did Kendrick get a laser to work with a Schmidt Cassegrain? By means of a clever idea. You’ve seen some of the modern collimators that allow you to observe the position of the return beam in a little window cut in the side of the laser, aincha? That’s what Kendrick did. Only instead of a bulls-eye target for the return beam, there was a grid. Adjust the secondary so the beam fell on the proper place on the grid, and you would be collimated.

The problem with that was knowing where on the grid that beam should go. The only way to find out was by collimating the telescope precisely the old fashioned way, on Polaris, first. You then inserted the laser, observed the spot on the grid where the beam hit, and marked that with a little sticker. When the scope went out of collimation, all you supposedly would have to do would be to adjust until the beam was on the sticker again.

A good and reasonable idea, one that sounds like it ort-ta work. Alas, it didn’t, not very well, anyhow. Given the mechanical exigencies of mass produced SCTs and their moving mirror focusing, returning the beam to the sticker rarely produced a dead-nuts-on (re)collimation. Yes, the Kendrick unit COULD be useful, as when you were faced with a sky full of sucker holes, your scope was badly out of collimation, and you wanted to see something in brief patches of clear sky. Under those conditions, the (no longer made as far as I can tell) Kendrick SCT Laser could produce an acceptable alignment.

But as amateur astronomers always do, we wanted more better gooder. We wanted to be able to do a precise collimation, and we didn’t want to have to tweak the scope in on Polaris first. That was a tough nut to crack, though, and nobody was able to for years. Not until word began to spread about a new SCT collimator from Hotech.

When I heard David Ho was marketing a new SCT laser, I was skeptical. Yeah, I knew the man’s reputation for quality, but we’d been down this road before hadn’t we? Still, I kept my ear to the ground, and soon divined that the Hotech Advanced CT (“Cassegrain Telescope,” I reckon) laser was entirely different from the Kendrick or any other laser collimator I’d heard tell of. I was told the unit was fully capable of producing perfect collimation all by itself. And I was hearing that not just from average fumble-fingered Joe Amateurs like yours truly, but from people whose opinion I respect, like imaging guru Craig Stark.

So, naturally, I was anxious to get my hot little hands on the CT for a review, and when David H. agreed to send me an evaluation unit, I was right excited. And maybe a little bit apprehensive. One other thing I was hearing through the grapevine was that using the CT required a far more complicated setup than just sticking a laser in the rear port. Would I be able to make the dang thing work?

When the collimator arrived, I was immediately impressed by Hotech’s attention to detail. This is a nice package, with the laser and its accessories contained in a pretty fabric case. In addition to the collimator itself, I found, among other stuff, a pair of eyepiece-like thingies, one 1.25-inch and one 2-inch. Turned out these are mirrors you place in the scope’s visual back in order to get the beam from the laser, which is pointed down the corrector end, propagating through the telescope’s optical system, hitting the primary mirror as well as the secondary.

How about the laser itself? It is a laser of a new type; actually it’s an enclosure equipped with multiple lasers. There are four of them mounted on the unit’s back. The whole shebang is powered by a single (included) CR123 battery.

What else? There was also some scary-looking stuff. Several finely ruled measuring tapes, a fabric strap with a metal buckle, and some funny looking plastic “tabs.” Looking at the tapes, I felt fear returning. In addition to being told I’d have to precisely square the laser with the front of the collimator, I had heard that would be particularly difficult with a Celestron SCT (all I own). Ah well, we’d cross that bridge, yadda, yadda, yadda.

Also in the shipping box was additional and, I believe, optional item, a tripod fine adjuster. You’ve no doubt seen these before: altitude-azimuth fine-tuners that attach to a photo tripod’s head. If you are contemplating the CT, I urge you to get one, as being able to make fine adjustments of the laser is extremely helpful, and can preserve your sanity and your hairline. A sturdy tripod is also desirable—the CT is mounted on a ¼-20 thread tripod for use. I used our Manfrotto, though I found an el cheapo Focal tripod (K-Mart) was at least useable. The fine adjuster is more important. The Hotech furnished adjuster is not exactly a premium item; the one I received was sticky in altitude at first, but it worked fine, which is all that matters.

What next? A look at the manual. If I can find fault anywhere with the CT system, it is with the manual. It is sufficient, OK, good enough, but could be better. Some of the pictures in this laser-printed sheaf of pages are too small and too dark. And some of the wording is a bit awkward or unfamiliar: “focuser” instead of “visual back,” “intercept” when “overlap” is meant, “tangent” when “perpendicular” would have been a better word choice, etc. However, the instructions are, again, good enough; especially when used in concert with the instructional videos available on Youtube. I have suggested to Mr. Ho that it would be nice to have the manual on a CD or DVD as an Acrobat file with larger color pictures. I also think it would be good for the videos to be on an enclosed disk.

Let me make sure I am clear about something rat-cheer muchachos. I know you are used to me being cavalier about and joking about instruction manuals. I’ve often told y’all that the first thing I do when I get a new piece of kit is throw the consarned instructions in the old rubbish bin. Not this time. Uh-uh. READ THE INSTRUCTIONS. Then read ‘em again—several times. Watch the videos. Then watch them again, several times. I guar-ron-tee that if you don’t, you will never, ever figure this thing out. And keep them instructions at your side your first time using the CT. You will need to look at them again.

“Hokay. Time to get started. Gimmee them dadgum instructions.” Which was when I hit the first landmine. At the get-go you are warned not to do the collimation on carpeted or wooden floors, only on a sturdy surface with no give. Waaalll…I got news: Chaos Manor South ain’t got nothing but wood floors, and I suspect many other folks, even those who don’t live in ancient Victorian manses, have the same. I could go outside, but one of the beauties of this rig, I thought, was that you could use it inside. When all was said and done I found I didn’t have any trouble collimating on a wood floor as long as I used our sturdiest tripod for the collimator.

The first step in the CT collimation procedure is getting the collimator properly square-on to the telescope. Doing that with a Meade is fairly easy. With the CT in mode 1 (it has several modes), which projects a crosshair pattern, you aim the scope and collimator at each other so three screws inside the tube near the mirror are illuminated. The trouble for a Celestron Man such as Unk is that Celestrons do not have three screws spaced at 90 degree intervals at the mirror cell end. I’d have to make my own marks via the measuring tapes and the “tabs.” Rut-roh.

Whether you’ve got a Meade or Celestron, before you can point the collimator to the screws or tabs, you first have to place the collimator the proper distance from the scope. That will depend on the scope focal length, but it’s less than one tube-length in front of the corrector for my C8. Start out about there, move the collimator and tripod forward or back until the crosshairs are their smallest, then move toward the scope till the crosshair pattern projected onto the collimator’s face extends to the first ring on the target.

Once you’ve achieved a good crosshair return on the CT’s face, you are approximately aligned as well as at the right distance. But you must be precisely aligned to produce a good collimation, and, as above, that’s a little more involved with a Celestron than a Meade.

Referring to the manual, I grabbed one of the lengths of measuring tape. That scary measuring tape. Actually, while it looked scary, it was surprisingly easy to use. No critical measurements are required. Wrap the tape around the rear cell and mark the overlap point on the tape with a pencil or whatever. Remove the tape, keeping it overlapped. Fold it twice so it’s one quarter its length, and mark a starting “0” position spot on the top of the telescope’s rear cell with a pencil or use some other convenient reference. My Celestron has a screw on the rear cell perfect for that. From there, use the folded tape to mark two “90 degree” positions on either side of the initial 0 mark.

Once that was done, all that was required was that I wrap the supplied fabric strap around the rear cell, fasten its buckle, and slide the three provided plastic tabs under it at the three marked positions. It seemed a little Rube Goldbergish, but worked fine and was more than precise enough. In practice, I found I could tell when the collimator was properly aimed just by eyeballing the three laser spots on the edges of the C8’s mirror. The tabs helped get everything lined up, though, and if you are collimating a Celestron, you should definitely use them. In fact, even if you have a Meade I think it might be a good idea to use the tabs; I believe they’ll speed up the process of aiming.

Getting C8 and CT positioned with the three laser beam crosshairs on the tabs (in the case of a Meade that would be “on the screws”) and the crosshair reflection on the right spot on the collimator target took some doing, crying, and whining the first time out. The problem is that you’ve got so much freedom of adjustment when you combine all the possible movements of collimator and scope that it gets confusing. One trick I did discover was that having a tripod with a tilt adjustment as well as altitude and azimuth saved me from doing a lot of leveling of scope and collimator.

How do you keep out of trouble and resist the urge to throw the whole thing against the wall? FOLLOW THE INSTRUCTIONS! If you do, you’ll find the alignment process is a two step affair with no mystery to it. First you aim the laser at the tabs (or the screws), then you aim the telescope so the projected crosshairs are centered in the first target ring on the CT. You keep doing these things in turn, adjusting by small amounts till the tabs or screws are illuminated and the crosshairs are centered on the collimator.

Even with a fair idea of what I should be doing thanks to the manual and the videos, I easily spent a solid hour getting everything sussed the first time. Like anything else, though, what was difficult that first time was laughably easy the second. The second time, getting scope and laser lined-up took me all of 15 minutes.

Since, as SCT mavens will tell you, the Schmidt Cassegrain’s mirror can change position slightly depending on whether the tube is level or pointing at the sky, it might be a good idea to collimate with the laser elevated, so the tube can be at an up-angle. The first time, however, you will have your hands full getting the feel of things, and I urge you to get comfortable with the system with the CT and scope both level. Having the scope on an alt-azimuth type mount helps, too. A lot. While my C8, Celeste, normally rides on a German equatorial mount, I placed her on my Synta AZ-4 alt-az for collimation.

With scope and laser properly positioned near as I could tell, it was time to DO THE DEED, to collimate. Which turned out to be slightly anticlimacitic. Once you master the art of squaring CT and SCT, all you gotta do is go through the old “which screw do I tweak?” routine.

Before you can begin collimation, you must turn the rotary switch on the top of the collimator to one of its other modes. Mode One, which we’ve been using thus far, projects a crosshair only. Mode Two turns on the collimation lasers, and Mode Three provides a combination of collimation laser spots and crosshairs. I chose Mode Three so I could be sure the telescope was still properly aimed (I am quite famous for kicking tripod legs, day or night).

Only problem was that when I switched to Mode Three, I could only see one big laser spot. What the hey? I rechecked my alignment and everything was fine. I was badly puzzled. I could see three sharp little laser dots on the face of the CT if I adjusted things a certain way, but from the instructions and the videos I knew I should be seeing three fat spots. I fiddled and fiddled, but nothing helped. Was I done?

Thankfully, your silly old Uncle had the sense to read the instructions one more time. There was indeed an entry on “what to do if you can’t see the laser spots.” The first suggestion was to check the return mirror in the visual back. That seemed OK, though I had a rather difficult time getting the 1.25-inch model, which uses a compression ring system to hold it snug, tight enough. OK. What next?

The second troubleshooting suggestion was slightly confusingly worded, but the meaning was clear. The telescope focuser should be close to the in-focus position it would assume with an eyepiece inserted directly into the visual back. Hey! Wait a minute! The last time I used Celeste has been with the Stellacam II and the Meade f/3.3 reducer, which throws focus way off from visual. Maybe…

Sure enough…some turning of the ol’ focus control and three laser spots magically appeared on the target. With them visibile, the rest is easy. If they are not all on the same bulls-eye ring, twiddle the collimation adjustments till they are. Since Celeste’s were somewhat off, I did that very thing. The instructions caution you to check your scope on Polaris after your first time collimation, just to be sure the collimator (and you) are setup properly.

That very night, luckily, I’d scheduled a trip to our local club darksite. I admit to being just slightly apprehensive when I turned the scope to the North Star and defocused slightly. I sure didn’t feel like going through a full-blown collimation session. But I didn’t have to. The diffraction rings were nicely concentric with the star centered. I didn’t have the seeing to check the appearance of the first diffraction ring of an in-focus star, but I will.

Yep, I’m not quite done yet. Look on this as a preliminary report. I plan to do a more in-depth one in my column, “Uncle Rod’s Cracker Barrel” in the next issue of Amateur Astronomy Magazine. In addition to seeing how close the CT can really get collimation, I want to see how much I can improve my setup time. Next time I’m going for “five minutes.” I will also try a different, older C8 OTA we have around here, one that ain’t been collimated in years and is no doubt substantially off.

“But what’s the quick-look verdict, Unk?” I hope to improve my setup time, but this unit will never be as quick to use as a Newtonian collimator. On the other hand, it’s likely to be significantly quicker than using an artificial star in the daytime. It works, and it does not require a lot of space. Hell, it hardly requires any space. It’s nicely made, and while the instructions/videos can be improved, they got me through my first time. Yes, there is a learning curve involved, but most worthwhile things have one. Expect to spend some time figuring out the CT, but when you get to that “OH YEAH!” moment, I suspect you are gonna be right happy with this thing, muchachos. Yeah, I know it ain't exactly cheap at $455.00. But for many of us that will be well worth it, and is less than some of us have got used to payin' for one more eyepiece. I give it one thumbs up, and, after another week or three of working with it, I hope to be able to give it two.

Next Time: We’ve had some nice, clear weather and your silly old Uncle is just TEARING UP the Herschels. Naturally you will hear all about it in the first of two H-Project reports next week.

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