ASTRO: Arp 184/NGC 1961 reprocessed

Being snowed in here until the township gets its plow working again to
plow the township road 1km from me I'm snowed in so am processing like
crazy. Weather too poor for imaging with all the blowing snow. All the
Honey do projects require getting to town for supplies so I'm free to
process night and day until the road can be kept open.

This is a reprocessed Arp 184/NGC 1961. Since 1961 was the year I first
did deep sky imaging with my 10" f/5 Cave this one has held some
interest for me. Problem is it is at nearly 70 degrees so spends nearly
all its time in my Polaris Tree. When I took this data over 2 years ago
I had to do so over many nights. Even then trees (pine needles anyway)
crept into the image making a mess of the stars and the background.
Flats don't compensate for pine needle obstructions! My ability to
handle this was limited back then. So I decided to reprocess the image
using my improved skills and larger tool set. While I now could deal
with the stars and background better there's a loss of resolution due to
diffraction effects of all the needles I couldn't eliminate. The trees
have continued to grow so doubt I can even do this well again unless I
do some trimming. Since they are 100 feet tall that is a bit beyond my
ladder's reach and I'm too old to try climbing them. Even a cherry
picker can't reach the branches I need to reach. This will have to do.

This time I was able to bring out the many HII regions in this galaxy.
Considering it is about 180 million light years distant these must be
huge compared to those we normally see in galaxies. In angular size
they are about the same as those in M101 at only 25 million light years.
The distortion to this galaxy is very hard to explain. While it is a
member of a small group of galaxies at the same distance (the three
largest other galaxies in the image are members of this group) none show
any hint of distortion so didn't cause the distortion. The other often
cited reason would be a merger but the papers I found say this isn't
likely. Maybe not but either this guy is intrinsically distorted or the
product of a long ago merger. I prefer the second choice.

Out of the Sloan survey field NED has distance data on only the three
other members of its group in the image and one quasar at 7 million
light years very near the galaxy. It's faint and I won't try to point
it out. Those interested can look it up at NED or download the DSS
image of it. It is IXO 29. Which stands for "Intermediate-Luminosity
X-Ray Object."

Arp's image
http://nedwww.ipac.caltech.edu/level...ig_arp184.jpeg

14" LX200R @ f/10, L=8x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Rick
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Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".