Rick,

beautiful image, although the left part of the image seems to be out of
focus.
Most of the picture looks great. I have imaged this nebula with a UHC
filter, which certainly helps.
Your image is deeper even without narrow band though.
I'd really like to know the nature of this nebula, while you are probably
right that it is no planetary nebula (too red for that) it looks unusual for
a HII region too.

Stefan


"Rick Johnson" schrieb im Newsbeitrag
. com...
Sh2-116 is also known as Abell 71. The latter is a mistake as it isn't
a planetary nebula but an HII region. It is "embedded" in the much
larger SH2-115 which is centered well southeast of my image. Sh2-115
really needs to be shot in H alpha with a wide angle telescope. So its
outskirts show up poorly in my image. I can't find much on this object,
not even a distance estimate. It is located in Cygnus not far from
Deneb which cast a nasty gradient across the image. Removing it without
removing nebula covering the entire image wasn't easy nor done all that
well. Another reason for H alpha data. Since the distance to Sh2-116
is unknown there's no way of knowing how it relates to Sh2-115 that is
also in my image. It may be in front, in it or beyond it. No way to
know. So the appearance of Sh2-116 being in Sh2-115 is likely only an
illusion but there's no way to know for sure either way from what I
could find.

I tried something different with the color data, taking only 1 20 minute
image rather than 2 10 minute ones as I usually do. When putting the
color together it really popped nicely. Usually I have to enhance the
color some but this time I actually turned it down slightly! Never had
that happen before. A couple other images I've taken this way did show
better color but I still had to give it a bit of help. Why things were
different this time I don't know.

Also I tried 20 minute rather than 10 minute luminosity subs. This did
bring up my background level some so I was closer to being sky limited
as far as system noise was concerned though still quite far from it.
But many stars saturated. This left me with great color in the bright
stars in the RGB but all white in the saturated stars of the combined
LRGB. So I reprocessed the luminosity image keeping the max level down
to about 200 rather than the max of 255. Then when I added the color it
worked well. I then used mask to bring up the cores to 255 but keeping
most of the star below this level. Lots of work but it did the trick.
Doubt I'll use many more 20 minute subs for the L layer unless the star
field is rather dim. Think I have a couple more shot this way to
process however.

Some images of this object show a green nebula just to it's east and an
even brighter one well to the southwest. These images were made from
DSS plates using a pseudo green created from the IR image. It appears
that image picked up ghosts from Deneb that created nebula like ghosts
the pseudo green process turned into green nebula. That had me confused
for a bit until I figured out what was going on with those images.

14" LX200R @ f/10, L=2x20' RGB=1x20'x3, STL-11000XM, Paramount ME

Rick

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