Sunday, September 22, 2013
Destination Moon Night Two: 23 Down, 277 to Go
It’s been a while since I spoke to y’all about my Moon project, over three months. But that’s not because I’ve lost interest in Luna. It’s because of the fraking weather. As I have said before, this has been absolutely the worst summer for observing I remember since 1994. I dang sure haven't given up on my project to image the Moon’s top 300 features, which I outlined here, I just haven't been able to do anything about it, muchachos. Not till last Saturday evening, that is.
Compared to what we have had lately, the weather Saturday afternoon was turning out to be real nice. It was clear, if a little hazy, and while temperatures were not that low, in the low nineties, the humidity was more bearable than it has been for months, somewhere in the 60% range. And a beautiful Moon just two days past First Quarter would be hanging in the sky till the wee hours. Time for me to hit the Possum Swamp Astronomical Society observing field.
At our little slice of dark sky heaven at sundown, I wasn’t overly surprised to be alone. I’d put word on the PSAS Facebook page that I'd be at the dark site for a Lunar run, but I suppose most of the membership can observe the Moon from home. Our many and ancient trees down in the Garden District make that purty much impossible for me.
I left the runway lights of the private airfield we use for observing on as a deterrent to baddies like Mothman and the Little Grey Dudes from Zeta Reticuli 2 and got to work setting up. What exactly did Unk set up? My current Moon picture rig, Mrs. Emma Peel, the Edge 800 SCT, on her VX mount. Yes, I know aperture is as important for Lunar and planetary work as it is for the deep sky, and that Big Bertha, my NexStar 11, might have been a better choice. The problem with that is Unk is lazy and getting lazier.
Camera? That would be the successor to my much-loved SAC 7B, the ZWO ASI120MC. I am testing another new planetary cam, the Mallincam SSI, but until I get some software problems (no doubt caused by your silly old Uncle) ironed out, that one is benched. This would only be my second time using the ZWO, but given my good initial experience with it, I expected great things.
One thing would be different from the first outing with the ZWO: I’d be using a different computer program to control it. One wise thing the ZWO folks have done is spend their time making their camera drivers as good as they can be rather than developing a control program of their own. The result is the ZWO will work with most of the software Solar System imagers are using today, including Sharpcap, the program I used for first light with the ZWO.
Sharpcap is a great program. It is not feature-laden, but it is very easy to use. That made it a natural for first light with the ASI120. As you know, I am not immune to the allure of the More Better Gooder, howsomeever, and had been hearing a lot about the soft used by the crème de la crème of planetary workers, Firecapture. I downloaded a copy and gave it a try indoors not long after I got the camera, but it tended to lock up the computer.
Then, just a few weeks back, I learned Firecapture’s author, Torsten Edelmann, had released a new beta that was purty much guaranteed to work with the ZWO. Lotsa boys and girls were giving it good notices, and a look at the Firecapture website showed the new one would do just about everything except make Unk’s biscuits in the morning. So, I decided to give it a go. I’d keep Sharpcap at the ready, of course, in the event things went south with the new FC version.
After I got Emma on her mount, I spent a few minutes preparing the Thermacell bug repeller. The mosquitoes weren't bad at sundown, but the deeper twilight became, the fiercer the bugs would no doubt become. Thermacell dispersing its funny but not unpleasant smell, I sat and twiddled my thumbs waiting for Polaris and some alignment stars to appear.
I had the best of intentions, y’all. I’d do a 2+4 go-to alignment with the VX followed by an AllStar Polar alignment. That was my intention, but I got antsy. Diana looked so beautiful hovering over the field in her shining silver gown that I just couldn’t wait for stars. I aligned the RA axis of the mount north as well as I could with the aid of my compass, kicked on the mount’s power, and told the VX to do a Solar System Alignment.
I’d used my phone to provide exact time, and I’d been careful with the compass, so I wasn’t too surprised when the mount stopped within a degree or so of Hecate. I centered her up, hit align on the hand control, and we were off to the races. I knew tracking wouldn’t be perfect with such a casual polar alignment, especially given that I’d be shooting at about f/25, but it ort ta be good enough. I’ve even been told a little drift makes it easier for Registax to properly align and stack the frames of .avi movie files.
Hokay. Time to get rid of the diagonal and eyepiece and mount the camera. I don’t insert the ZWO directly into the scope. Instead, I use it with the Meade 1.25-inch flip mirror I bought a dozen years ago to go with my ill-fated Starlight Xpress cam. A garden variety Barlow, an Orion Shorty, is inserted in the flip mirror’s rear port. It might be “garden variety,” but this inexpensive Barlow is one of the best I’ve ever used. The ZWO camera with an IR block filter screwed onto its 1.25-inch nose-piece goes in the Barlow. Finally, the eyepiece tube of the flip mirror is filled with my good, old Meade 12mm reticle eyepiece. When you are dealing with higher focal ratios and tiny imaging chips, a flip mirror ain’t just a help, campers, it’s a freaking requirement.
I plugged the ZWO’s USB cable into the Toshiba laptop, which responded with a reassuring bing-bong, and lit off Firecapture. The program recognized the camera immediately and ran perfectly all night long. I need to spend more time reading the software's help files, but it is so well-designed and intuitive I had no trouble operating it.
|Click the pix for larger versions...|
Where to start? Copernicus, natcherly. For me this massive “new” crater is the most beautiful feature on the Moon. I think so now, and I thought so back when I was a little bitty kid just starting to explore Luna. When I was so green I didn't even know how to pronounce its name. I called it “copper-nick-us” till I was corrected by one of the younguns in our Backyard Astronomy Society who'd somehow learned how the crater’s name was supposed to be said.
Copernicus was just about perfectly placed on this evening. Not so close to the terminator that detail would be lost in shadow, but not so far away that its massive ray system would steal the show. I flipped the flip mirror up, centered the crater in the cross-hairs, flipped down, and focused up the onscreen image.
Which was easy to do. Despite the fact that I had selected the ZWO’s maximum resolution mode, a healthy 1280x960, Firecapture was still delivering over 30 frames per second. With images refreshing at such a rate, focusing was a dadgum joy. So much easier than it was with the SAC 7’s pitiful 5-f.p.s. at 640x480. I fiddled with exposure and gain till I got a good looking image, and recorded a 30-second sequence that resulted in dern near 1000 frames being captured.
No, it really don’t get any better on the Moon than this. Copernicus ain’t just large at 93 km across (I always amaze the youngsters at public star parties by telling them Copernicus would extend over halfway between Biloxi and New Orleans), he’s fresh and relatively untouched by the ages, being “only” 800 million years old. The floor is unspoiled and its terraced walls are steep and sharp looking. With camera or eye, there’s plenty here to see here, from the complex central peak that rises 1.2 km high, to the ray system that begins to “shine” not long after sunrise on Copernicus’ walls.
There are quite a few interesting small craters in Copernicus’ neighborhood, both those with names, like Fauth, and those that have only been given letters. Unfortunately, there was only one other crater in the field on my hit-list of 300 features from the old Norton’s Star Atlas. If Copernicus looks fresh and new, Gay-Lussac is the opposite. This crater, named for a 19th Century French Physicist, has walls with an “eroded” appearance and a floor that’s a tumbled down mess.
After Copernicus the Great? That was easy: to the Moon’s southern highlands where the huge crater Clavius was sitting in the Sun. Clavius, famous as the site of the Moon base, Clavius Base, in 2001: A Space Odyssey, is a huge thing 225 km across. It is the third largest crater on the Moon’s nearside. What makes it incredibly interesting, though, it not just its size, but the detail on its floor, and especially the arc of good looking craters, Rutherford and the “unnamed” Clavius D, C, N, and J.
In addition to the letter-craters and Rutherford, which intrudes into one of Clavius’ walls, the floor is peppered with many other smaller pits that stand out well. The better your scope, camera, and seeing (which is the most important thing of all), the more fascinating detail you will see here.
Plato and the Alpine Valley
Hokay, back north again to the more uncluttered part of Hecate’s shining visage. The area of Plato and the Alpine Valley is a wonderful one for visual observers and imagers alike. It is, above all, a place of challenges: the Plato Craterlets and the rille down the center of the Alpine Valley (Valles Alpes).
Plato is a great dark lake of a crater that easily dominates the whole area. It’s very old, about 3.84 billion years, close to the same age as nearby Mare Imbrium, and it is large, 109 km in diameter. Due to its position near the Moon’s limb, it looks oval to us, but is actually round. Except for a few possibly volcanic pits here and there, the Moon’s craters were created by impacts, and that process is unable to produce a strongly elongated crater.
There are plenty of other large and sharply defined craters on the visible face of the Moon; what makes Plato special is its floor, which was obviously flooded with basaltic lava. And what makes that floor especially interesting is the presence of numerous small craterlets scattered across it. There are four craterlets in the 3 km diameter range that are doable visually with 12-inch telescopes under good seeing and at high power.
Not easy, mind you, but doable. I’ve actually detected the two largest of these little guys with an 80mm refractor when there is a high Sun angle at Plato. At that time they are easy enough to see as white spots. Seeing them as actual craters, though, does require considerable telescope horsepower, good seeing, and patience.
Imaging the craterlets is way easier. The most prominent ones showed up almost any time I pointed my old SAC 7 at Plato, and in a modern camera like the ZWO they actually look like, yeah, little craters. The better the seeing the better they look, of course, and the more of ‘em you record.
Plato is notorious as the site of reports of Transient Lunar Phenomena, “TLPs.” Moon observers have reported odd lights and hazes on the floor of the crater for ages. I’ve never seen anything like that in all my years of lunar observing, but I still hope to see something strange here or somewhere else on the Moon someday. I tend to doubt the reality of TLP, but I also doubted of the reality of Venus’ Ashen Light—till I saw it for myself.
The Alpine Valley is another of the Moon’s true wonders. It is a wide—10 km at its widest point—lunar valley, “Valles,” that extends for over 160 km. What caused it? Probably crust slumping along a fracture line. One look at its floor and it is easy to see it was also heavily modified by the lava that flooded it.
Valles Alpes is visible in the tiny scopes; that’s not the challenge. The challenge is the narrow rille that extends for almost its entire length. I’ve been after the rille for years, but have never really seen it visually. I’ve “suspected” it at best. It’s not that easy with a camera, either. The rille is visible in the shot I did of the Alpine Valley on this night, but is not prominent unless I ramp up the contrast enough to make the picture ugly. Probably need to come back to it with the C11 and more focal length some night, I reckon.
At the opposite end of the Alpine Valley from Plato, we run across a couple of nice craters, Archytas (30 km) and Protagoras (22 km). Also in the region is an interesting semi-“ghost” crater, Egede (36 km), that was almost erased by lava. That floor is covered with numerous craterlets, making it even more cool looking. Unfortunately, it was not on my “300 list” so I moved on.
Where did I move to? I didn’t stay in the Alpine Valley area. There were clouds gathering and I wanted to get as many more important features as I could before they moved in. What’s the most prominent crater on the Moon at First Quarter after Copernicus? Tycho, of course.
Even when Tycho’s enormous ray system is subdued by a low Sun angle, the crater, which nestles in the jumbled terrain of the southern highlands not far from Clavius, stands out. Why? Because it is sharp and bright compared to the terrain it is set in. It is barely 100 million years old and couldn’t be more distinct from the worn-looking craters around it. It is 86 km in size, and features both terraced walls and a complex central peak.
My sweet little ZWO did a nice job on both Tycho and the nearby list craters Pictet (63 km), Saussure (55 km), Orontius (123 km), and Sassides (91 km) as well. The secret to getting a good portrait of Tycho and company is, as always, a low Sun angle, but not too low. At mid-morning, the whole region is just freaking awesome.
This great crater is only about 90 km from Clavius, but nobody talks about it much. I don’t know why. It is magnificent. Sharply defined, it is 146 km in size and has a fascinating floor that’s pitted with numerous craters and craterlets. Most of the craters around Longomontanus are interesting, but are “anonymous,” having letters instead of names, and were not on my list. Wilhelm was the exception. It is old, pre-Nectarian, around 4 billion years old, but it has stood up fairly well. About half its walls are badly eroded, but mostly it is still well-separated from the surrounding terrain and attractive.
Longomontanus and Wilhelm captured, those dadburned clouds moved in with a vengeance. It looked like they might eventually move off, but I wasn’t in the mood to wait ‘em out. The humidity had spiked up, the bugs had come in a second wave that required me to replace the Thermacell’s repellent pad with a fresh one, and I was on the verge of “hot and tired.”
Back when I was a sprout, I had to wait days or weeks to see my Moon Pictures, till daddy could be persuaded to drag out his developing tank, enlarger, and all those wonderfully stinky chemicals. That wait is one thing I do not miss about film astrophotography. As soon as I got back to the Old Manse, was able to take quick looks at my image files and begin processing the 50 gigabytes of images. OK, I’ll admit it: I had one eye on the computer and one eye on Svengoolie, who was showing (the color) Phantom of the Opera.
How did the few shots I processed that evening and the rest, which I did Sunday morning, turn out? Purty good. Actually, they would have knocked me slap out even fifteen years ago, but I reckon I have been spoiled by the new way of Lunar imaging and what its top practitioners are accomplishing, and I was already plotting how to do just a wee bit better. I will get that stinking Alpine Valley rille yet, muchachos.
Next Time: Pore Old Blue
Tarnation unk, same target, same night, and the same 2 craters. Here I was feelin good about my videos and you had to just blow me out of the water. Well sir, all I can say is its your fault I gotta go buy the ZWO camera! At least that's what I'm tellin the wife.Post a Comment
All kidding aside, awesome pics and a GREAT blog!
Thanks for all you do!
All kidding aside, awesome pics and a GREAT blog!
Thanks for all you do!