Sunday, June 15, 2014

 

Destination Moon Night Five


Life is full of adjustments, muchachos, but it sure seems like I’ve had more than my share to make over the last four years. First, I moved from the Navy’s AEGIS destroyer program to their big LPD amphibious ships. Then, as that program began to wind down, it was time to—shockingly—think “retirement.” Then came act 3, moving out of good old Chaos Manor South.

Despite all that, I tried not to slow down in my observing. In fact, I kicked it up several notches. Hell, I completed what will probably turn out to have been the biggest observing project of my life, The Herschel Project, where I viewed all of William and Caroline Herschel’s multitudinous galaxies, nebulae and star clusters. That wasn’t all; I also started a couple of subsidiary observing projects, including one I called “Destination Moon.”

That particular program goes back a lot farther than a mere four years, to my first days in amateur astronomy and my first love in the sky. The Moon was not the first object I saw through a telescope; that was the Whirlpool galaxy through the 12-inch Cave Newtonian at Springhill College when our Cub Scout Den visited their observatory. The Moon was the first thing I put in the field of a telescope myself, however.

As I have written before, the first telescope that could be considered “mine” was not the Tasco 3-inch Newtonian Daddy rescued from a pawn shop, but a 6-inch f/12 reflector built by one of the Old Man’s colleagues at the TV station where he was an engineer. 

That person had become interested in making a scope and had fabricated the 6-inch from the ground up. All he bought was a mirror blank and abrasives. Everything else—tube, focuser, mount, eyepiece —was handmade. Unfortunately, as is sometimes the case with ATMs, he found he liked building better than using. When the OM mentioned his son had become obsessed with astronomy, that kind soul offered to turn his telescope over to me.

What was the scope like? When Daddy got it home after somehow loading it into the backseat of his 1960 Ford Fairlane, li'l Unk was excited, sure, but maybe not as impressed as he thought he'd be.  Even by the simpler standards of 1960s amateur astronomy, the 6-inch was not much. Its tube was a white painted length of stovepipe. A long length of stovepipe, a smidge over 6-feet long. The mounting? A battered boom microphone stand the TV station had cast off. This mount’s “slow motion” was provided by a screen door spring. The mirror wasn’t old but looked it. Instead of having it aluminized, the maker had silvered it himself, and that non-overcoated silver had soon begun to deteriorate in our salty Gulf atmosphere.

Cave 12...now that's a scope!
And yet…to me this hulking thing was still beautiful. Beautiful with potential. While even a greenhorn eleven year-old could see the 6-inch was definitely a poor relation of Springhill’s beautiful Cave, that didn't matter. I knew, knew, it would show me things in the sky. Beautiful and mysterious things. Starting with that big Moon ascending in the east. It was full, and surely that would be the perfect time for lunar gazing. More to see, right?

What little Unk didn't know was that “full” means “noon on the Moon.” The Sun is high in the lunar sky, there are no shadows, and craters and mountains become nearly invisible. Oh, you can make out the bright ring-shapes of younger craters and the ray systems of Tycho, Copernicus and a few others. It’s also a good time to look at the Moon’s seas, the mare, but you are denied the beautiful, detailed terminator, the sunrise/sunset line that is a welter of detail.

All li'l me knew was there was a huge yellow Moon rising on a gentle spring night and I now had the power to explore it. Hell, this telescope made my classmate Stephanie’s 60mm AC Gilbert reflector look pitifully small. All I had to do to get started was get the Moon in the eyepiece.

Which wasn’t easy. My first problem was the tube’s length. Even given the Moon’s reasonably low altitude as 9 p.m. came on, aiming the tube in its general vicinity resulted in the eyepiece being over my head. Solution? Mama had recently made the proud purchase of a new dinette set, and one of the chairs from the old one was stationed in the carport for the Old Man's use when he worked on his radio projects in the utility room. I grabbed it and standing on the seat I could reach the eyepiece.

I looked into the eyepiece but no joy. I repositioned the tube best I could. Nada. The scope’s builder had neglected to provide it with a finder, and even the long focal length eyepiece (maybe 30mm) gave a magnification high enough, about 60x,  to make locating anything crazy hard. Even today, I suspect it would take me a while to get the Moon in an eyepiece at that magnification by sighting along the tube. Worse, that tube was riding on a mount (if’n you could call it that) shaking like a sinner in the hands of Elmer Gantry.

But…finally…I noted a glow in the field, zigged a little up, zagged a little right, reversed directions and—dang—there she was. I couldn’t possibly have seen much detail on a full Moon, but even today I remember that first look as the most wonderful view of the Moon I have ever had.

My hollering, “Daddy, you have GOT to come look!” also summoned the three neighbor boys who were my regular playmates. Apparently, they’d been doing a little weekend camping out in the backyard and had been about to pack it in before things got too spooky (we knew from watching the Early Show that “Full Moon” equaled “Wolfman”). The five of us, Daddy, me, and my three companions, spent the next half hour admiring Luna.

Until the youngest of the neighbor boys burst into tears. Evidently, he’d developed the theory that Santa Claus didn't live at the North Pole, but on the Moon. He was only six and maybe he’d been influenced by another Early Show masterpiece, the very odd film Santa Claus Conquers the Martians. When he couldn’t see Santa in the big scope as he’d expected, it was just too much.  He ran home bawling his head off, his brothers said goodnight, and that was the end of my first glorious night on the Moon.

Which brings us around to this latter age. I still like to look at the Moon. Hell, one of the few things I could do from the old Chaos Manor South was drag the StarBlast or the 3-inch SkyWatcher refractor into the front yard for a quick look at those well-loved features. In the go-go days of the Herschel Project it was nice to occasionally pull back from the dim and distant and visit my old friend Diana again. It was also a little sad. Every time I looked at the Moon, I’d remember how much better I knew her surface when I was a sprout.

There was a time when I knew Earth’s satellite as well as I knew Mama and Daddy’s subdivision. That familiarity stuck with me well into the 1970s, until I turned almost completely to the deep sky and that hard-won knowledge began to fade away. One evening in the Old Manse’s front yard when I realized I couldn’t remember which Mare was Tranquilitatus, I decided I wanted the Moon back; I wanted to know Hecate again.

How would I relearn the Moon? When I was a little feller, I took Sir Patrick Moore’s advice and began to draw. I went a couple of clicks beyond what my mentor suggested, however. Rather than 100 prominent features, I resolved to draw all 300 shown in the beautiful old map in my 15th edition of Norton’s Star Atlas. That dern sure taught me the lunar surface. What if I did that again? Sorta.

I wasn’t up for doing all that sketching, but how about imaging? I’d been hearing about this cool new planet-cam, the ZWO ASI120MC. Didn’t cost much. What if I got me one of them? So I did, and began touring the Moon’s surface with it, which has been a ball. It’ s been slow going thus far, but I can now image the Moon on any clear night from the New Manse.

Hazy Moon o'er the New Manse...
Anyhoo, last week, with the Moon approaching First Quarter, I decided it was time to get Destination Moon back on the rails. Unfortunately, conditions weren't too good, in addition to the haze that’s been filling our skies of late, even when it is “clear,” there were scattered clouds. Normally I’d have said “frak it” and spent the night in front of the dadgum cable TV. With Miss Dorothy out of town visiting daughter Beth in DC, however, I was bored and lonely and wanted something to take my mind off that. Out came the CG5 and Celeste, my good old 1995 Ultima 8 OTA.

I inserted the ZWO in the rear cell of the C8 via my flip mirror, or, actually, into a 2x Barlow inserted in the camera port of my faithful Meade flip mirror—which I’ve been using for over a decade. If you want to do planetary imaging at long focal lengths, a flip mirror is a must. No matter how good your go-to, your scope may not put targets in the field of a small planetary camera chip at f/20 or f/30. A flip mirror lets you center your object in a crosshair eyepiece, ensuring it will be in the frame of the camera. When it’s in the crosshairs, FLIP the flip mirror down to send images to the camera.

If you’re using a planet-cam like the ZWO, you have to hook it to a computer, of course—no built in storage or image viewing with ‘em. I plugged in the camera’s USB cord and got a reassuring BING-BONG. The ZWO is so simple to run you wouldn’t think anybody would ever have problems with it. It’s powered by the USB bus, and images and camera control signals run over that single USB connection. Nevertheless, Unk being Unk, I’ve managed to get the poor little thing badly confused a time or three.

One of the best things about my planetary setup is the program I use to control the camera and capture images, Torsten Edelmann’s freeware masterpice, Firecapture. When it comes to planetary image capture programs, I’ve used ‘em all, from the simple like Sharpcap to elaborate ones like K3CCD Tools, and there is no doubt Firecapture is the best. I won’t talk your ear off about its multitudinous features or the fact that it is so simple to work that even a caveman—or Uncle Rod—can do it. I’ll just say, “If you are into Solar System imaging, DOWNLOAD FIRECAPTURE.”

The other half of my lunar imaging equation is the ZWO. Even at full resolution, 1280 x 960, my (color) ASI120MC will still capture frames at 30 - 35 fps. As I have said before, I haven’t found anything this little camera doesn't do well. I’ve used it for spectroscopy, Solar (hydrogen alpha) imaging, and may even get around to trying it on the deep sky someday—quite a few people are turning in remarkable deep sky images with the little sucker despite its small chip.

If that sounds interesting, I recommend you read my buddy Sean Walker’s excellent review of the (monochrome) ZWO in the July 2014 issue of Sky and Telescope. While Sean talks about the black and white camera, much of what he says is also applicable to the color one, and his review is dern sure information-packed. Another great review of the camera, this one by Jeff Turner, can be found here

Firecapture...
Anyhoo, brought up Firecapture (which I believe is now included on the DVD shipped with ZWO cams) and got ready to do some Mooning. Before I could proceed further, howsomeever, I had to get the CG5 mount aligned. That was simple enough. If you are using a GEM mount, all that matters is that you do a reasonable polar alignment and get the mount tracking at sidereal rate. I usually go so far as to at least do a Solar System alignment with the CG5 and VX—for a couple of reasons.

First off, I am lazy; it’s easier to let the scope slew to the Moon on its own than it would be for me to stand there mashing a direction button (or pushing my Logitech Wireless Wingman’s joystick when I am using NexRemote). For a Solar System alignment, you choose your object, the Moon in my case, and the mount slews to where it thinks the target should be given a perfect polar alignment, no cone error, and precise time. Since NexRemote uses PC time, which is generally purty accurate, the main variable is polar alignment. Just using a compass to “polar align” will usually ensure the scope stops with Luna somewhere close to the Telrad’s illuminated bullseye.

I use the Solar System Alignment rather than a normal 2 + 4 star NexStar alignment for my lunar work because I don’t want to wait till it is dark enough to see alignment stars. Our seeing down here on the Gulf Coast is usually good, but in my experience it is often best right after sundown. I get rolling as soon as it’s dark enough for the Moon to look reasonably contrasty on the laptop’s screen.

Alignment finished and the Moon in view of the flip mirror’s eyepiece, I focus up. My flip mirror is set up so what’s in focus in the eyepiece will also be close to focus on the ZWO’s chip. The flipper has a helical focuser that can be locked down with a knurled ring. When I first got the camera, I achieved good focus onscreen and adjusted the focuser so the Moon was also sharp in the eyepiece. I may still have to tweak focus a mite for the camera, but usually not much.

After I’ve got focus, I select my first lunar feature by moving the scope while looking through the flip mirror eyepiece. It has a much wider view than the camera, and it’s way easier to find what I want that way than by slewing around while viewing the image on the computer. When I locate what I’m looking for—usually a feature not far from the terminator, flip goes the flip mirror, and I go to the computer.

The rest is simplicity itself. I don’t mess with many of Firecapture’s numerous controls and features—though I may want to someday, who knows? I just frame, focus, and expose. With my target on the display, I’ll tweak focus till it is as good as I can get it—a motofocus system of some kind is as important as a flip mirror for good Solar System imaging results. When the Moon is sharp, or what passes for sharp most of the time—even way down here images will almost always be swimming/simmering due to seeing—I set my exposure.

I learned how to do that way back in ought-three when I was chasing Mars:  adjust shutter speed till the subject looks good and bright on the screen, and then shorten the exposure so the image looks slightly too dim. That ensures a better frame rate and prevents overexposure, which is worse than underexposure.

When I’m satisfied with the preview image, I mash Firecapture’s record button. How long do I run a lunar capture? I find that around 800 – 1000 frames is usually plenty when seeing behaves. The ZWO will deliver that many frames in just a smidge over 30-seconds. I’ll generally do a couple more sequences of the target as “insurance” and in hopes of hitting a patch of superior seeing. Then it’s onto the next feature and repeat as needed.

On Night 5 of the Destination Moon Project, I wasn’t able to go as long as I needed or wanted. Dadgum clouds saw to that. Oh, and I was still figuring out where to set up the scope and screwed up. When I’d finished my first two target areas, the Moon was in pine trees. So it goes with your old Uncle Rod.

Theophilus and company... 
Thus ended a too short lunar run. After the scope was put to bed, I retired inside to the cool and bug-free den for a little Rebel Yell and a little cable TV. The Yell was right good. The TV? Not so much. Of COURSE there was nothing at all on the 300 plus channels we get. I sat for a while watching the Weather Channel, got right tired of hearing predictions of more stormy weather, and ended the evening with the pea-picking BBQ Pit Masters. I was tempted to have a look at my images, but I know better than to do that. Even poor ones look mucho bettero in the morning. Off to bed went your weary Uncle.

Next morning after my requisite two cups of Community Coffee, it was time to run my Moon pictures through the amazing Registax 6. The process of doing that is a subject for a whole ‘nother blog, but if’n you’ve never heard of Registax, what it does is take the .avi movies produced by a planetary camera and stack the best frames into still images. It then allows you to apply freaking amazing sharpening tools to those images. We’ll talk about it some Sunday, but for now I’ll just say I did all that and was pleased with my results despite haze and seeing that was below par for the Coast.

“Cut to the chase, Unk, what did you image?” My first shot was the area of the remarkable crater Theophilus. I’d already essayed it for an earlier Destination Moon installment, but couldn’t resist “just one more” of it and its companion craters to start the evening off.

My favorite computerized lunar atlas, the only one I use, Virtual Moon Atlas, calls this 101km crater an “exceptional formation,” and it is that in spades. It is a sharp, steep-walled crater that shows tremendous detail, including a central mountain 1400 meters high composed of four separate peaks. As you might expect given its fresh appearance, the crater dates from one of the more recent if not most recent lunar epochs, the Eratosthenian (3.2 billion years to 1.1 billion years). This is one you have really got to see. As Patrick Moore says (in The Amateur Astronomer) “[Theophilus] is one of the most magnificent of all the lunar craters.”

Theophilus is not alone. It is in a group with two other craters of similar size. Cyrillus, with a diameter of 98km is just a little smaller than Theophilus. There is quite a difference in their ages, however, as you can tell just by looking at Cyrillus, which has an unmistakable eroded look. It was formed in Nectarian times, nearly 4-billion years back. Frankly, if it weren’t for nearby Theophilus, nobody would pay much attention to Cyrillus. It is soft, soft, soft with three central peaks that look like nothing more than rounded nubs.

Posidonius...
The last big crater in this group is Catharina to the south of Cyrillus. This 101km formation also dates from the Nectarian, and is almost as worn looking as Cyrillus. Its walls do look a little steeper and sharper, but not much. What’s to see inside Catharina? A couple of ghost craters on the floor accompanied by some small craterlets and several small craters that have intruded on Catharina’s walls.

I probably should have quit while I was ahead, y’all. By the time the last Theophilus footage was in the can, conditions had degraded badly. I wasn’t about to give up the ship without capturing at least a couple of new ones for the Project, though.  Which included another truly magnificent crater, Posidonius. This 98km “walled plain” formed in the Upper Imbrian period (3.2 – 3.8 billion years ago) is one of the most identifiable and remarkable sights on the Moon. What makes it look so cool is a flat, almost raised looking floor that is home to a looping network of rilles, lunar valleys. There’s also a fresh looking crater, Posidonius A, almost smack in the center. Finally, there’s 51km diameter ghost crater, Chacornac adjacent to Posidonius.

And that was that, muchachos, a measly two more added to the total. I sure hope to cover more ground next time, and believe I will if the weather gods allow it. I’ve got a better idea where to set up in the yard and I’ve re-familiarized myself with the ZWO to the extent that my fumbling should now be at a minimum (ha). Current Destination Moon tally? 50 down, 250 to go.

Next Time:  More Star Rainbows…

Comments:
Happy Father's Day! Uncle Rod.
Many more returns, fer sur!

 
Hi Rod, I am very happy to read you again after a very long break when I read and we shared our opinions with amateurs on sci.astro.amateur usegroup until is death in 2007. Also happy to see that ou always practice astronomy ;-)
Thierry Lombry
Luxorion
 
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