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.
Copernicus
 |
| 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.
Gay Lussac
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.
Clavius
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.
Tycho
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.
Longomontanus
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
Comments:
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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.
All kidding aside, awesome pics and a GREAT blog!
Thanks for all you do!
Jeff
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All kidding aside, awesome pics and a GREAT blog!
Thanks for all you do!
Jeff
# posted by 
: 7:29 PM
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