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Old May 26th 16, 11:45 PM posted to alt.binaries.pictures.astro
Stefan Lilge
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Posts: 2,269
Default Sh2-241 plus mosaic with vdB 65

Rick,

that looks very nice, especially the mosaic with vdB65 with it's contrasting
colour.
I am sure that I have imaged Sh2-241 as I remember it looking like a comet,
but I don't find the image on my harddisk, maybe I have it under a different
name...

Stefan


"WA0CKY" schrieb im Newsbeitrag ...


Sh2-241 is an emission nebula in southern Auriga just below vdB65. I
found several distance estimates. All put it over 15,000 light-years
distant. The only one with error bars says 17,000 light-years +/- 3500
light-years. It is at least 4 times further away than its neighbor, vdB
65.

Again I was fighting severe clouds that hampered my image. I used the
best data from 2 nights to try and piece it together, some was taken the
same night as vdB65 but while I had good conditions for some of the
vdB65 image conditions had gone down hill by the time I moved to
Sh2-242. H alpha came from the second night, most of the color and
luminance from the first.

SIMBAD identifies the brightest part of the nebula around the star as
the reflection nebula GN 06.00.9. That appears completely over taken by
the emission nebula. The blue data for the brightest part of the nebula
is a bit bluer than normal for an emission nebula but not by a great
deal. Maybe it is my poor conditions that prevents me from seeing it
all that well. The faint part of the nebula is also known as LBN 825.
It is also listed as LBN 824 a reflection nebula. Though again I can't
see the blue color I'd expect for a reflection nebula. To the west of
the fainter portion is an odd yellow-orange object. It is listed as
LEDA 135933. NED shows it as a galaxy but under classification say HII.
I suppose this means it is a galaxy with strong HII emission. It is
listed as being 400 million light-years distant. It is the only galaxy
with a redshift measurement at NED in my field. There's a star just
about on top of the galaxies core. In the 1" per pixel image it does
show as two separate objects if you look closely. The bright one being
a field star.

With so little to annotate I wasn't going to do an annotated image but
then noticed 5 asteroids I'd overlooked so did prepare one to point
these out. All Green data was taken the second night (several days
later) so green is missing from the brighter asteroid trails.

After processing I noted it partly overlapped the vdB65 image though was
offset to the west somewhat. I didn't realize then when processing and
posting vdB 65. I did combine both into a mosaic at 1.5" per pixel and
cropped the blank regions that this created. Since conditions were a
bit better for much of the vdB65 image the frames were a nightmare to
match. Not being a mosaic expert this is the best I could come up
with.

Data for the Sh2-241 image:
14" LX200R @ f/10, L=4x10', Ha=3x30', RGB=2x10', STL-11000XM, Paramount
ME

Rick


--
WA0CKY