Sunday, November 24, 2013

 

Destination Moon Night 3: 37 down, 263 to Go


Actually, I could have called this installment “The Little Camera that Could” in honor of the star of my Saturday night show, the ZWO ASI120MC, one of the new astro cameras out of China that are taking the planetary imaging world by storm. The inexpensive ZWOs with their small chips and many small pixels are perfect for high-resolution imaging of the Sun, Moon, and planets, but that’s not all they can do, muchachos.

I haven’t tried the camera on the deep sky (yet), but I have been amazed at what folks have accomplished there despite the ZWOs’ little chips and lack of cooling (I understand a cooled ZWO is planned). No, you can’t capture huge swathes of space, but the little cams have produced surprisingly good pictures of planetary nebulae, galaxies, and globular clusters.

I hadn't used the ASI for anything but the Moon until recently, when I did a few shots of the Sol with my friend Jonathan’s Coronado solar scope at the just finished Deep South Regional Star Gaze. I’d heard rumors that the ZWO cameras didn't work well with a hydrogen alpha scope, but considering the images I got with my color camera on my first attempt with Hα, I gotta rule that talk bull-spit (this is a family friendly blog, y’all).

As they say on the pea-picking TBS late at night, though, “THAT’S NOT ALL!” I’ve also used the ASI120MC for spectroscopy. With the aid of the program RSpec, which I’ve been testing, and a Star Anlyser grating, I was able to easily—yes, easily—capture a detailed spectrum of Vega. Unfortunately, that was my first outing with the spectroscopy set up, and I didn't have things set up quite right. A quick consultation with RSpec’s helpful (and talented) author, Tom Field, edumacated ol’ Unk as to where he’d fouled up. So, I was anxious to give Vega another try, and last Saturday night seemed like a good time to do it.

There’d be a near First Quarter Moon in the sky, not a very good time to go after galaxies, but Luna wouldn’t prevent me from taking Vega’s spectrum. And I could combine that with shooting some more images for my Destination Moon project. I’d barely scratched the surface of the 300 lunar features I’ve set as my imaging goal for the DM project, and needed to get back after it.

Sol in Ha from DSRSG 2013...
I was still a wee bit weary from the exertions involved in packing for, attending, observing at, and returning from a major star party the previous week, y’all. But so what? I’m retired now, and I got to thinking I ought to be doing a lot more observing than I am. The big old oak trees that surround and envelop Chaos Manor South don’t allow me to do much from home, but the Possum Swamp Astronomical Society dark site is only 45-minutes away, and I now have the one thing I lacked for the previous three decades: time.

That’s just what I’d do on this weekend, I thought:  spend the early evening at the dark site imaging my silv’ry girl, Diana, and when she began to sink I’d switch over to spectroscopy and get Vega and maybe a few more stars besides. I’d be able to use the ZWO for both purposes, wouldn’t need too much gear, and I’d be able to make it a reasonably early evening now that that fricking-fraking Daylight Savings Time is done.

Saturday started out with a beautifully blue sky, but the weather-saps insisted clouds were on their way, and I had the feeling they were correct for once. The formerly cool (for us) temperatures were spiking back up into the 80s, and the humidity was rising. As the day wore on, the skies remained mostly clear, but there was a line of stuff low on the western horizon, never a good sign, and I began to wonder whether I would be able to beat the advancing front.

At four o’clock it wasn’t raining, at least, and I stuck to my maxim, “If it ain’t raining, head to the dark site.” At least I didn’t have too much to pack, not compared to a Mallincam run:  Mrs. Peel the Edge 800 SCT, the VX mount, the tackle box that holds most of my accessories, and one large Tupperware container with the rest of the astro-junk. The imaging gear consisted of the ZWO and accessories in an aluminum tool attaché case I got from the cotton-picking Harbor Freight, and my Toshiba Satellite laptop. With sundown coming at quarter after five, I hit the road at 4:30.

Pretty, but not so encouraging...
The farther west I went, the higher those damned old clouds climbed. By the time I was out of the city, there was a substantial bank of thick gray suckers in the southwest. Y’all will be proud of me that I didn't even consider turning Miss Van Pelt around. I continued on to the PSAS field and got to work setting up—in a right big hurry.

Looking at the reddening western sky, which seemed to give the lie to “red sky at night, sailor’s delight,” I estimated I might have an hour at best, so there was no time to lose. Old Unk scurried, campers, scurried. I originally planned to do a good rough—through the hollow polar bore of the VX—alignment on Polaris, which would be followed by a full six star go-to alignment and an AllStar polar align. But Polaris was not visible yet, and when it got dark enough to see the North Star, I was purty sure it would be behind the clouds.

Since I couldn't see Polaris, I used my compass to get the mount’s azimuth as close to that of the North Celestial Pole as I could. We are lucky down here that magnetic declination (deviation) is small, so a compass can get you close. The mount’s R.A. axis elevation was still set for the Feliciana Retreat Center, and I left it alone, since FRC is just a smidge north of the PSAS dark site in latitude.

That was the extent of my polar alignment. Now came mount go-to alignment. I’d left the NexRemote cables, game pad, and game pad receiver at home, since I knew I wouldn’t want to devote time to setting all that up with weather on the way. Y’all know I ain’t a fan of the Celestron Plus hand control that came with the VX mount, but all I’d be doing with it would be a simple Solar System Align and aiming at targets with the direction buttons.

Lit off the mount, entered time and date and such, and selected Solar System Align from the menu. Chose “Moon,” and the mount and Mrs. Peel slewed that-a-way. I was surprised they stopped as close to Luna as they did—maybe a half degree away. I suppose the fact that I’d used exact time off’n my iPhone helped a little. If the sky cleared or the clouds stopped in their tracks and I had the chance to do some spectroscopy, I’d bite the bullet and do a 2 + 4 go-to alignment and an AllStar polar alignment before I got started with that. From the way the evil dark things were flooding the sky from the west, I didn’t reckon I’d have to worry about that, howsomeever.

Mrs. Emma Peel and VX...
The clouds apparently kept my fellow PSASers at home. I was alone, and while I have been known to get spooked at this slightly lonely airstrip, I was perfectly comfortable all by myself on this night. I was way too busy to worry about the depredations of the dadgum Skunk Ape and his despicable pals, Mothman and the Little Grey Dudes from Zeta Reticuli 2. I will admit I left the runway lights on, but why not? I was imaging the Moon and wouldn’t need a bit of dark adaptation.

With scope more or less aligned, it was time to get the rear cell setup done. When I am imaging the Moon and planets at high magnification, I always use a flip mirror. My first experiments with video back in the early 90s, which involved an ancient Sony camera with a vidicon tube, revealed that even with a precisely aligned finder it’s near impossible to get even the Moon on a small video camera chip without major exertions.

Flip mirror on Mrs. Peel’s (ahem) rear, and 12mm reticle eyepiece in the flip mirror focuser, it was time to set up the cam. We used to use eyepiece projection to get long focal lengths for Lunar and planetary work, but that has gone the way of the dodo. Barlow projection provides much better images, and with today’s small chip planetary cams, you don’t need the huge focal lengths provided by eyepiece projection.

How much focal length would I need? I like to shoot the Moon at about f/30, but what I’d seen through the eyepiece in the course of getting the mount aligned showed that would be too much on a night where the seeing started out bad and would undoubtedly get worse. A 2x Shorty Barlow (Orion) went in the flip mirror’s 1.25-inch rear port rather than my 3x APO Owl Astronomy Barlow, and the ASI120MC went into the Barlow via its 1.25-inch nosepiece.

One other thing you will need in addition to a flip mirror and a Barlow for Lunar imaging with the color ZWO is an IR block filter. Imaging chips are very sensitive at the infrared end of the spectrum, so you’ll usually want to block most of that. If you don’t, your pictures will have a strong red/pink cast that it difficult to correct during processing. If you buy a color ZWO camera, you’ll find the maker has thoughtfully included a 1.25-inch IR filter that screws onto the camera’s nosepiece.

You need a software program to run the camera and handle image capture, of course, just like with any other astronomical cam.  When I first got the camera, I started out with the freeware program Sharpcap. It works very well with the ZWO, and is simple and effective. I’d still be using it today if I hadn’t discovered another freeware soft, Firecapture.

Maurolycus
Firecapture has nothing to do with the old Firewire data format; it is a program designed to control astronomical cameras, especially for Solar System imaging, and, frankly, campers, does more than I will ever call upon it to do. Not only will it control filter wheels and motorized focusers as well as cameras (a large selection of cameras), it will even calculate ephemerides of Solar System objects. Best of all, it is easy to use. Only caveat? If you want to use Firecapture with a ZWO camera, make sure you download and install the v2.3 beta. Earlier releases tended to lock up with the ZWO cams.

Camera and software ready, I went back to the eyepiece, centered a target feature on the 6-day old Moon, the complex and interesting crater Maurolycus, flipped the flip mirror up to send light to the camera, went back to the Toshiba, and saw...absolutely nuttin’. Oh, for god’s sake. What now? I didn't need this with weather coming in. I managed to keep my cool somehow, and it turned out all I had to do to get the crater in view was tweak exposure and gain, which were still set for imaging through the solar scope. 

The live image, the video (like other planetary cams, the ZWOs output a .avi video stream), of Maurolycus looked OK, especially after I fine-tuned focus, but just OK. The seeing was even worse than it had been when I’d aligned the scope, but it’s amazing what Registax 6 can do, so I fired off several 25-second sequences anyhow. That yielded around 800 individual frames even at max resolution, 1280 x 960, and that is usually more than enough frames for a high resolution lunar image.

Maurolycus has always been one of my go-to lunar features. It’s big, 114 km in diameter, and, while it is located smack in the Moon’s southern highlands, it is far enough from the limb to look round. Though it was formed purty far back, during the Nectarian period about 3.9-billion years ago, it has a fresh, deep look. At this point in the lunation, the nearby large crater Barocius, which can look soft when the Sun is higher, also stood out well.

This was hardly the first time I’d imaged Maurolycus; I took quite a few shots of it with my old SAC 7B modified webcam. This crater always looks good; surrounded by large amounts of detail, it gives your images a “high resolution” look, even if they are actually a little soft.

Theophilus
Next up was one of the most photogenic features on the Moon, the crater trio of Theophilus, Cyrillus, and Catharina. I chose to concentrate on Theophillus, cutting off part of Catharina. While all three look good together, Cyrillus and Catharina look old and fuzzy. Theophilus is sharp and just loaded with detail including an exquisite central peak complex. This big 101 km diameter crater is likely fairly young, probably dating from the Eratosthenian period about 1 – 3-billion years ago. When the seeing is better than it was on this evening, it’s easy to capture lots of small detail including rilles and countless craterlets.

Agrippa and Godin, a pair of craters not far from the shores of Mare Vaporum, are usually fairly uninteresting. Both appear round and deep with Agrippa being 46 km across and Godin about half that size at 21 km. While their floors are fairly detailed when visible, neither is really much to write home about. The real scenic landmark to visit here is the wide rille just to the north of the craters, Rima Ariadaeus, a graben, an area where the ground has slumped, which runs east/west for some 220km. This whole area is a welter of rilles, small craters, and ghost craters. I thought even normally staid Agrippa and Godin looked very photogenic on this night with their floors still covered in inky black shadow.

Delambre, a medium sized 53 km crater sitting near the edge of Mare Tranquilitatus, is not one I remembered, though I’m sure I must have observed it numerous times over the years. This is a nice region, with a crowd of craters large and small, and certainly deserves a look. The main interest at Delambre is its rough looking floor, which I suspect on a good night would give up some craterlets, and the crater’s beautiful terraced walls.

With conditions worsening by the minute, I wasn’t sure whether or not I’d get an acceptable image of Plinius. I did, but just barely, and may revisit this Eratosthenian crater on a better night. It deserves it. This fresh appearing 43 km formation stands out since it is offshore out in Mare Tranquilitatus near a cape, Promintorium Archerusia. Of particular interest are the crater’s detail laden floor and a complicated-looking central peak.

Agrippa and Godin
When I had Plinius in the can, a look up showed Luna was soon to be bathed in clouds, and was already covered by a thin layer of haze. Actually, it seemed as if Diana might skirt the cloud-bank for a while, but the haze and the seeing near it were so bad, and the last exposure of Plinius so soft, that it was obviously time to pull the Big Switch. It didn’t look like rain was imminent, but it didn't look out of the question, either, so I didn't tarry.

From the time I’d mashed Firecapture’s record button on Maurolycus, I’d had little more than half an hour of imaging, so I was back at good, old Chaos Manor South and sitting in the den with a big libation of the pea-picking Rebel Yell at 9 in the freaking p.m. Just in time for my fave Saturday night show, Svengoolie. Unfortunately, the film he was showing was Ghost of Frankenstein, my least favorite among the Universal monster movies. Frankenstein’s Monster on the witness stand in a brightly lit courtroom? Reeeeee-diculous, y’all.

Svengoolie purty much a bust, and it still early, I couldn’t resist sitting down to the Toshiba Satellite and test-processing one of the sequences of Maurolycus with Registax 6. If you’ve used the previous versions of the premier image stacking program for planetary observers, the new one, 6, won’t hold too many surprises. Some new options have been added, especially to the wavelets screen, but nothing that should bring you up real short. If you are new to Registax? This tutorial by Paul Maxson does the best job I’ve seen of getting you started simply and quickly.

If you are new to Firecapture and are using a color camera like the ASI120MC, there is one thing to get used to. You need to debayer your sequences before you process them with Registax; you have to convert the camera’s raw video to RGB color. You can allow Firecapture to do that on the fly as you image, but that causes a fair amount of processing overhead and usually results in lower frame rates. Firecapture comes with a little app that will allow you to debayer sequences in batches or singly after the fact, and that is what I do. I also often convert my final images to black and white. I just prefer monochrome for the Moon.

Delambre
After I’ve stacked in Registax and sharpened the resulting still image with its amazing wavelet filters, I normally do a little fine-tuning. Registax has its own image processing tools, but I find it easier to use Adobe Photoshop or, increasingly, Adobe Lightroom. I began using Lightroom to process and organize the terrestrial images I shoot for my books and magazine articles, and find nearly as powerful as Photoshop and much better than Photoshop’s “Browse” function at keeping my hundreds and hundreds of pictures organized.

Lightroom is much less expensive than Photoshop, a measly 149 bucks for the downloadable version vice 650 smackers for Photoshop. For most imagers, Adobe Lightroom is more than capable enough, and for working photographers it actually has some advantages over Big Bro.

So what did I think of my latest batch of  Moon pictures when I'd Registaxed 'em all the next day? As you can see above, not bad, not bad at all—considering the conditions. If nuttin’ else, muchachos, it showed, once again, that you will always get more out on the observing field than you will sitting in front of the dadburned boobtube.

Next Time: New Kid on the Software Block...

Comments:
Adobe Photoshop CC - Creative Cloud can be purchased for far less then the old price you quoted. I believe there is a special until Dec 2 or 3rd where you can subscribe to Photoshop for $9.99 per month and that includes the latest version of Lightroom [LR]

 
Some people may be up for the CC and monthly payments...not me. Too old fashioned, I reckon. LOL

 
Hey I know this is off topic but I was wondering if you knew of any widgets I could add to my blog that automatically tweet my newest twitter updates.

I've been looking for a plug-in like this for quite some time and
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Please let me know if you run into anything.
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I'll keep my eye out...but haven't seen anything like that, I'm afraid...
 
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