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:
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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]
# posted by 
: 11:26 AM
: 11:26 AM 
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Post a Comment
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# posted by : 4:47 AM
: 4:47 AM << Home
