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Old August 25th 13, 08:30 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: NGC 1907.TXT

NGC 1907 is the open cluster "companion" to M38. I was surprised that
my short exposure time picked up nebulosity around the cluster. Of
course there's quite a bit in Auriga where the cluster resides. Still
it isn't seen often with the cluster, especially in short exposures like
I usually take. Both the H alpha and a small blue reflection nebula
surprised me. Especially considering how heavily obscured my skies were
that night. I picked a star cluster due to the night's transparency
being poor for going faint. I expect this nebulosity would be rather
bright on a good night. So why is it rarely seen in images of the
cluster? Is it processed out as a gradient?

NGC 1907 consists of some 35 to 50 stars depending on which source you
use. I found this extended to its age and distance as well. WEBDA puts
the cluster at 5100 light-years and gives it an age of 370 million
years. Wikipedia says 4500 light-years and 500 million years old. I
found other distances and ages as well.

So how does this fit with M38? Are they true companions? WEBDA says
M38 is 290 million years old and is 3500 light-years distant while
Wikipedia says 220 million years of age and 4200 light-years. So by
WEBDA neither the distance nor age of the two are close so they aren't
related. Wikipedia says they are nearly the same distance but even
further apart in age so again unrelated. They are apparently just line
of sight companions.

There are two asteroids in the image. The one in the cluster (toward
the northeastern edge) is (87314) 2000 QJ3 at magnitude 18.2. The other
is much fainter and difficult to find. It is near the right edge about
the same level as the bottom of the small reflection nebula just inside
the extent of the H alpha seen in my image. Both have about the same
length of trail that is tilted about the same. It is (344507) 2002 RZ10
and shines at magnitude 19.5 according the Minor Planet Center. Due to
my poor transparency this night neither are as bright as I would expect
for those magnitudes.

This is my last successful November 2012 image. More were tried, the
weather had other ideas.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick
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