Well, I guess I've learned one important lesson about imaging, namely that
the processing can take every bit as long as the photon-gathering, if not
longer. No worries, though, it's a nice way to spend a rainy evening. If I
can't be out under the stars, it's nice to be looking at their electronic
incarnations, especially when it was my gear that put those electrons
together the previous night.
Here are the images that I've managed to put together from my data. The
names are fairly self-explanatory, I think...
http://nebula2.deanza.edu/~marek/images/astro/m3_photoshop_01.jpg
http://nebula2.deanza.edu/~marek/images/astro/m35_photoshop_01.jpg
http://nebula2.deanza.edu/~marek/images/astro/ngc_2158_detail.jpg
http://nebula2.deanza.edu/~marek/images/astro/m46_photoshop_01.jpg
http://nebula2.deanza.edu/~marek/images/astro/m46_pn_detail.jpg
http://nebula2.deanza.edu/~marek/images/astro/pleiades_photoshop_01.jpg
http://nebula2.deanza.edu/~marek/images/astro/ngc4565_photoshop_01.jpg
http://nebula2.deanza.edu/~marek/images/astro/alnitak_flameneb.jpg
Here's a big-ish M42:
http://nebula2.deanza.edu/~marek/images/astro/m42.jpg
All in all, I've been quite pleased with how well everything worked on this
first foray into imaging. A lot of things seemed to have come together:
Polar alignment, CG-5 tracking, 20D functionality, ED80 image quality, I'm
pleasantly surprised with it all. I wonder how much of it - like the polar
alignment and the focusing - was beginner's luck?
The processing on these images was fairly simple, if rather time-consuming
on my computer, which seems to struggle with large programs. (Stuff like
Registax and Photoshop can be pretty taxing, but it pulled through.) My use
of Registax was exceedingly simple: I understand almost nothing about its
controls at the moment, so I just boneheaded my way through it, clicking on
the green-underlined buttons. I don't know how much good the Registax-ing
did, but hopefully it was worthwhile. In most cases, I combined about 10
20-second images. After Registax, I opened up the resulting bitmaps in
Photoshop, and did some basic processing. I played around with Curves and
Unsharp Mask, and occasionally fiddled with the color balance a bit. I
cropped, too, which was usually helpful in framing the object and in taking
out some comatic stars near the edge of the field.
The two images that surprise me the most are the m3 and m42 images. I'm
really amazed that a handful of short exposures on a 3-inch scope can
result in that much detail. I'm really surprised to have resolved stars all
the way across m3, and to have gotten so much detail in the m42 nebulosity.
The M35 and M46 images recorded a lot of stars, which make the clusters
almost 'blend' with the rich Milky Way background. It's kind of like
looking at these objects in a big scope. But both of these objects have
colorful little "goodies", too. I was pleased at how well the M35 image
revealed ngc2158, the more distant oc in the background. Interestingly
enough, it looks to me as though the ngc cluster is reddened somewhat by
interstellar dust, which makes sense, given its likely greater distance.
It's cool to be able to see that sort of stuff in such a simple image. And
in m46, there's that pn whose ngc number I can never remember. It looks a
bit greenish-blue, which fits with being an OIII-heavy planetary nebula, I
guess. This is the sort of thing that imaging really excels at. I love
visual observing, always will, but imaging is the bees knees when it comes
to anything involving color and DSOs.
The NGC 4565 image is fairly faint; I squeezed as much detail out of the
galaxy as I could without making the sensor pattern too egregious. I think
that in all of the images of extended objects, I should have just gathered
more photons. I think that if each exposure had been 30 seconds instead of
15 or 20, I'd have gotten a lot more detail in things like NGC 4565. Still,
it's neat to be able to make out the full length of the galaxy, the dust
lane, and the nucleus.
The shot of Alnitak and the Flame Nebula is pretty heavily stretched. I
just wanted to see if I could recover some data from an otherwise
blank-looking area of the image. Some of the heavy-duty flare around
Alnitak is from light cirrus cloud, I think.
The Pleiades image doesn't show any of the reflection nebulosity. Again,
longer exposure times would probably have been a big help. But as an image
of the Pleiades themselves, I think it does okay.
Well, it's 1 am once again, and once again I'm beat. It's good to have been
able to shoot some stuff and to see the results. This imaging thing is
really cool. Just today I suddenly realized that the list gurus may have to
get on my case about taking my threads to TAC-Imaging. Wow, who'd have ever
thunk it?
Marek Cichanski
Received on Tue Mar 28 01:03:10 2006
