Sunday, July 20, 2014
Destination Moon Night 6: 64 Down, 236 to Go
As I said the other day on the freaking Facebook, muchachos,
you’d think that with all the heat and haze we’re getting on the Gulf Coast,
we’d have some good seeing to go with it as a consolation prize. Nope. Despite evening
skies that look like milk, the air has not been overly steady. Not steady
enough to make me want to attempt Solar System imaging, not normally.
Several things conspired to get me out in the backyard with
C8 and ZWO camera, howsomeever. One was that I’ve got accustomed to doing a lot
more observing than I used to. Especially compared to when I was a cotton
picking wage slave. I kicked my observing hours up a notch when I retired in
2013, and have already kicked ‘em up a couple more notches now that I have a
backyard where I can do some observing.
Another reason to hit the backyard despite the punk seeing was
that I was seriously in arrears with my Destination Moon observing project. I thought moving to Pine Needle Drive would
allow me finally to make real progress in imaging my chosen 300 lunar features,
but ‘tain’t been so. Weather and other projects have conspired to keep “DM” in
the doldrums.
Finally, while I’d been using my fave lunar software, Virtual Moon Atlas, for years and years (hard as it is to believe it’s been
around that long), there was one of its many features I had never tried. That
bugged me.
What’s that Skeezix? What’s a Virtual Moon Atlas? Back when it first came out, I liked to call the
software “Megastar for Moon watchers.” Today, maybe that should be “SkyTools 3 or TheSkyX for lunar observers.” It is what I hoped for from the
beginning of the computerized amateur astronomy revolution, a lunar charting
program that would free me from paper Moon maps like like SkyTools freed me from printed star atlases.
The need for a computer charting application for the Moon
was even direr than it was for the deep sky. While TheSkyX will go far deeper than even the Millennium Star Atlas, Millennium will still get most amateurs as
far out into deep space as they need to go.
Not so with the Moon. The primary tool for most “Lunatics”? Antonin
Rukl’s time-honored Atlas of the Moon.
It is a wonderful book by a wonderful man. I treasure my autographed copy, and
am proud to say I had the honor of showing Mr. Tony the Moon through my C8,
Celeste, one autumn night. While his atlas is still beautiful and still useful,
it leaves something to be desired data-wise. The number of features it shows
and labels make it about as useful for the advanced lunar observer as Sky Atlas 2000 is for advanced deep sky
observer. That is, “good,” but plenty of gaps.
Beyond the higher level of detail Unk supposed a
computerized lunar atlas could offer, there was another way one would be much
more useful at the scope than a print atlas. The fact that your scope inverts
or reverses images doesn't mean much for deep sky work, but it can make the
jumbled lunar highlands almost impossible to navigate. With a computer Moon
atlas, you could flip or rotate Luna easily.
A computerized atlas seemed like a natural, but there wasn’t
one. Unk waited and wished all through the 1990s—in vain. There was no Moon Megastar despite the explosion in
astronomical computing. Then, finally, in 2002, it happened. Astronomy software
guru Patrick Chevalley (Cartes du Ciel) and Moon guru and
passionate lunar observer Christian
Legrand released version 1.0 of their freeware Virtual Moon Atlas.
The rest, like the bright boys say, is history. While there
was a commercial lunar atlas program competing with Virtual Moon Atlas for a while, it soon became evident that Patrick
and Christian’s “VMA” was everything lunar observers had hoped for, and the
pay-to-play program faded away.
What’s VMA do? That is the subject for a full blog entry
like this one, but suffice to say the
program puts an incredibly detailed (and beautiful) Moon on your desktop. It
also brings a host of lunar resources to the amateur. In bad old days, the only
way you could hope to get a look at “professional” lunar atlases like the Lunar Orbiter Photographic Atlas of the Moon
(LOPAM) was if you had a big university and its library nearby. VMA puts stuff
like that at your disposal for the price of a download.
Much as I loved VMA—it reawakened my long dormant obsession
with the Moon--there was, as above, one feature of it I had never tried: goto. I know what you are thinking,
“Shoot, Unk, why would you need goto for the fraking Moon?” If all you do is look at a few prominent objects—Tycho,
Copernicus, Plato—you don’t need goto for the Moon anymore than someone who
only looks at M13, M42, and M27 needs goto for deep sky observing.
If, however, you are after more subtle lunar features or,
especially, you are imaging lunar features, prominent or not, with a Solar
System camera, goto can be a Good Thing. If you are after high-resolution pictures,
you image the Moon at high focal ratios—f/20 and above. At the high
“magnification” that imparts, small-chip cameras like the ZWOs have small fields of view. It can be a real
task to get even good, old Copper-Nick-Us
(as silly little Rod called Copernicus when he was knee-high to a toad-frog) in
the frame of a planet-cam.
How had I been working so far? Pick out a crater or other
feature on VMA. Walk out to the scope. Flip down the flip mirror to send images
to a reticle eyepiece. Locate the target using the hand control. Flip the
mirror back up to send the images to the camera again. Back to the computer to
do the exposure.
That wasn’t a productive way to work. If I were going to get
a move on with Destination Moon, I’d have to do better. I’d have to find a way
to do everything at the computer, like when I was doing The Herschel Project
with my Mallincams. I knew VMA included a goto system, and since I also knew it
used the ASCOM telescope drivers, I figgered it wouldn’t be too hard to get going. Hell, I probably
didn’t even need to read the consarned instructions (VMA’s help file).
Anyhoo, set up the good, old Ultima 8 on the good, old CG5 in
the good, old backyard and hoped for the best. At least I’d be comfortable no
matter what the pea-picking sky and scope did. Miss D. and I had purchased new
furniture for the deck that very day, and I was seated in a comfortable chair
at a nice table with a big umbrella that served to keep at least some of the heavy
dew off Unk’s pore old noggin.
With the pretty, gibbous Moon finally free of the trees and
the North Star peeping out, it was time for your old Uncle to get started. “Getting
started” this time was more complicated than on my last lunar run. No easy Solar
System Alignment tonight. I’d need the goto to be as good as it could be, I
reckoned, so I did a full-blown 2+4 alignment, followed by a (Polaris) polar
alignment, followed by yet another 2+4 to tweak the goto back in after moving
the mount to get on the NCP.
Alignment-polar alignment-alignment finished without
incident to speak of, I mashed “Moon” on the HC's Solar System menu, the CG5 made
her famous weasels with tuberculosis noise, and, when the mount stopped, Luna
was centered in the eyepiece of the flip mirror.
Cool. Next step was to light off Virtual Moon Atlas and choose the “Tools” tab from the menu on the
right side of the screen. I selected ASCOM’s Celestron driver, specified the CG5 and—I
thought—I was done. Where to first? How about Copernicus? That would be
immediately identifiable, you betcha. I typed C-o-p-e-r-n-i-c-u-s in the search
field in the “Information” tab, went back to Tools, and mouse-clicked the “Goto
Selected” button. The mount slewed a short distance and Celeste’s NexRemote voice intoned “Target
acquired.”
But was it? I fired up my camera control program—a really
great camera control program—Firecapture,
and had a look see. While the program indicated all was well with the camera, the
only thing that greeted your silly old Uncle’s peepers was a black expanse of
screen. Increasing exposure had absolutely no effect. Unk was lost in
circumlunar space, it seemed.
Maybe, just maybe, Unk should read them dadburned instructions after all. Doing so
indicated what my problem was: “Begin [by]
centering a well known formation in the eyepiece field and select it on the
map. Push the ‘Sync selection’ button for initializing telescope coordinates on
this position.” Well, there you had it. Unk centered Copernicus as per usual
with the gamepad I use as NexRemote’s
hand control, mashed “Sync selected” (in the Tools menu), selected Plato on the
chart, and tried another goto. Bam! There was everybody’s favorite dark-floored
crater near the center of the screen.
So what is the verdict on VMA’s goto function? It works well
and is hardly a frill. It allowed me to cover ground much, much more quickly
than I would have if I’d had to go out to the scope with the hand control and
hunt and center features manually for each exposure. How accurate was it? More
than accurate enough. Reliably centering lunar features at f/20 on a small chip
is a demanding task for a goto system, but the old CG5 came through with flying
colors. I did have to re-sync one time, but that was it and was hardly a
problem.
Having lunar goto allowed me to image 14 objects in the time
it normally takes to image 5. It would actually have been 15, but I kept spelling “Parry” P-E-r-r-y, and, naturally, VMA couldn’t find a crater with that name in
its database. Not only did goto make the run go quicker, it took some of the
stress away. I could tell conditions were degrading, but being able to click my
way to targets in a hurry meant I wasn’t sweating.
How about them conditions? From my first look at Copernicus, I could tell they were not gonna be as good as I’d hoped. Not horrible, but only fair. Good enough to continue Destination Moon, but not good enough for me to get excellent shots.
Destination Moon
Night 6
Beginning in the lunar highlands, my first stop was Blancanus, which is freaking amazing.
This steep-sloped 106 km diameter crater features terraced walls and a flat,
detailed floor with a nice central peak. So why don’t you hear more about it? There’s
not a word about Blancanus in Patrick Moore’s A Survey of the Moon, and it’s barely mentioned in Westfall’s Atlas of the Lunar Terminator, to
mention the first two lunar resources I grabbed off Chaos Manor South’s
bookshelf. Maybe because Blancanus’, perched on the southwest slope of the
great crater Clavius, is overshadowed by its more impressive neighbor.
Moretus is in the
same general area of the Moon, 378km to the southeast of Clavius Base. It’s a
lot like Blancanus—impressive, that is—with sharp, terraced walls 114 km in
diameter and a flat, lava-surfaced floor that hosts numerous craterlets. There’s
also a 2.7 km high central peak. Not too shabby, y’all.
That horse of a different color, the one you’ve heard tell
about, is Pitatus, which is 875 km
south-southeast of Clavius. Pitatus is, as Ernest Cherrington calls it in his
classic Exploring the Moon through
Binoculars and Small Telescopes, “The remains of what once must have been a
major lunar formation.” This 98 km crater is nevertheless immediately obvious
when the sun angle is reasonably low, and consists of soft-looking walls and a
floor of lava that flooded in from nearby Mare Nubium.
In addition to craterlets and a weathered looking central
peak, the main interest inside the crater is a network of rilles, Rimae Pitatus. The rilles that run around the crater’s
circumference inside the walls are particularly impressive. Those crossing the
center are more subtle, and didn't show up well for me under poor seeing. To
the west is the odd little crater Hesiodus A, which is composed of two
concentric “rings.”
Southwest of Pitiatus is 88 km diameter Wurzelbauer a badly damaged formation, that is even less “there”
than Pitatus. It consists of eroded, low walls surrounding a floor of ancient
lava. The western half of the floor is rough, while the eastern portion is
relatively smooth. A network of rilles crosses the eastern part of the floor.
Gauricus, just
east of Wurzelbauer, is like the two previous craters, badly damaged. It looks
a little fresher than Wurzelbauer, but not much. At 80 km diameter, it is
slightly smaller than its neighbor is, and features a flat lava floor dusted
with small craters. The most interesting thing about Gauricus is the ghost
crater, Gauricus F, situated in the northern area of the crater’s floor.
East of the preceding three craters is Hell. The formation is named for an 18th Century Hungarian astronomer, Maximilian Hell, not religious
mythology’s land of the dead, and doesn't look like Hell at all. It looks great,
a steep-sloped 33 km crater with a rough, “tormented,” floor. While not the sharpest picture I’ve ever
taken, my image picked up the basic details with the exception of the pretty
little craterlet near Hell’s center. I can make it out if I hold my mouth just
right, but just barely.
Southeast of Hell is Lexell—or
what is left of it. This 63 km formation is just shy of being a ghost crater.
While the southwest walls are still there, if eroded looking, the crater rim to
the northeast has almost completely disappeared under lava. The rough floor is scattered
with craterlets of varying sizes.
Kies lies to the west-southwest
of Lexell out in Mare Nubium. Like Lexell, but even moreso, 45 km diameter Kies
is close to being ghosted, with there
being a sizable gap in the walls to the west. There’s an odd protrusion to
south and some other barely visible details that hint at how magnificent this
crater must have been before the lavas of Mare Nubium consumed it. 157 km north
of Kies is the wonderful terraced crater, Bullialdus.
Mercator,
southwest of Kies, is, as you prob’ly guessed, named for the famous 16th
Century mathematician and map-maker. “His” crater, which is paired with the
similar and similarly impressive Companus, is 48 km across and features steep
walls and a flat, craterlet littered lava floor.
Adjoining Mercator on the west is Campanus, also
48 km in diameter. The walls of the two formations are separated by a rille that
was just barely visible in my image. There’s also a rille on the floor of
Campanus, but I just couldn’t pull it out on this night. I did pick up a couple
of craterlets and a small central peak, however.
Lubiniezky,
northwest of Bullialdus, is another crater that has suffered from intrusion by
Mare Nubium’s lava. While the crater’s walls still form a nearly complete 45 km circle,
the rim to the southeast is badly damaged and is completely missing along one
stretch.
There is nothing damaged looking about Eratosthenes, which lies on the shores of Mare Imbrium 300 km south
of the center of Copernicus. This 93 km formation has steep, terraced walls,
and a complex central peak composed of three separate mountains. A hallmark of this crater is the “tail” of
mountains stretching away to the southwest.
441 km northwest of Copernicus is the isolated crater Lambert set in the “waters” of Mare
Imbrium. 30 km in extent, it has steep slopes, a rough floor, and a rounded
looking central peak. The impressive “mountain,” Dorsa Stille, actually a
wrinkle ridge, is 70 km east and stands out like the proverbial sore thumb.
Timocharis is a
dang nice one to end on, a pretty and well-defined terraced-walled crater
north-northeast of Lambert. While not large at 35 km, its bright, steep walls,
terraced interior, and cratered central peak make it a standout.
And that was that,
muchachos. The seeing, never good, reached a crescendo of suckiness just as I
finished Timocharis. Suddenly, there were clouds, too. I tucked Celeste in with
her Desert Storm cover—one of the beauties of the secure New Manse is that I am
not afraid to leave the scope out overnight—and retired to the den for a tetch
of Yell and a couple of hours watching Survivorman eat bugs. If nothing else,
I’d got my lunar goto go-toing and moved destination Moon ahead a smidge. Not
bad for a hazy and hot July night in Possum Swamp.
Nota Bene: You can see all my lunar images from Night 6 on my Facebook Page, y'all...
Next Time: Down
Chiefland Way…
Comments:
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Do you now operate "remotely" from your patio? Where did you get the alien shirt?
# posted by 
: 4:54 PM
: 4:54 PM
Talking of those high f-stops now...
I was getting crummy results imaging the Moon with my Canon DSLR. The images were turning out a lot worse than my visual observations.
My best guess is it was the high f-stops i was using. Take an f/10 SCT and add a 2.5x or 5x Powermate on it, and now you have f/25 or f/50. But these little DX DSLR sensors are getting diffraction-limited by about f/11. So by f/25 and especially f/50 you'll be getting serious diffraction degradation. Which is just what i was seeing in fact.
Of course there's also field-curvature issues with a Powermate, but that' a different story.
So i wonder how the high f/stop diffraction issues impact these non-DSLR imaging sensors? Or do they?
I was getting crummy results imaging the Moon with my Canon DSLR. The images were turning out a lot worse than my visual observations.
My best guess is it was the high f-stops i was using. Take an f/10 SCT and add a 2.5x or 5x Powermate on it, and now you have f/25 or f/50. But these little DX DSLR sensors are getting diffraction-limited by about f/11. So by f/25 and especially f/50 you'll be getting serious diffraction degradation. Which is just what i was seeing in fact.
Of course there's also field-curvature issues with a Powermate, but that' a different story.
So i wonder how the high f/stop diffraction issues impact these non-DSLR imaging sensors? Or do they?
# posted by : 12:07 PM
: 12:07 PM
The secrets to high resolution lunar imaging? High focal ratio--about f/20 to start, small chip with small pixels, and, maybe most importantly...lots of frames 1000 minimum. The limitation isn't high focal ratios in most folks case, but _seeing_. ;-)
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