Thread: ASTRO: vdB 111
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Old April 25th 13, 06:01 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Default ASTRO: vdB 111

It might be a bit tough from town. van den Berg lists it as bright but
keep in mind the reflection nebulae around the 4 star, vdB 20-23 are
listed as very bright so this one is fainter than those but as vdB
objects go one of the brightest. Most are much fainter. Even for my
dark skies they aren't easy targets. I'll be interested to see what you
get. This is a July image so be a bit before it is well placed to put a
lot of time into it.

Rick

On 4/24/2013 4:10 PM, Stefan Lilge wrote:
Rick,

I just have put this nebula on my list...

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

VdB 111 is a reflection nebula in Ophiuchus around the star HD 156697.
According to The Sky 6 the star is a rather white F0III-IV star. As the
variable classification indicates it is a variable star that pulsates in
size more than in brightness. The range is listed at 6.50 to 6.52 which
would be hard to see visually. Since the nebula is very blue it would
lie a bit in front of the star to have a color much bluer than the star
itself. This is the same effect as the sky being blue from sunlight
shining through it. Our star is even redder than this one yet creates a
blue sky when it shines through it. When the nebula is behind the star
so just illuminated by the star it takes on more closely the color of
the star itself. The Sky 6 says the star is at a distance of 28,767,800
AU which would put it about 455 light years from us. This would be
virtually the same as the nebula's distance. What few images of it I
found on the net usually contain the comment that it is small and
uninteresting. Guess I don't see it that way but then nearly everything
out there I find interesting.

While there are some background galaxies NED had no redshift data on
any, all being galaxies from the 2 Micron All Sky Survey (2MASS) which
rarely had redshift data.

There's one asteroid down in the lower right corner of the image. It is
18th magnitude (215122) 1999 LG4. As usual, conditions were poor so even
this rather bright asteroid is very difficult to see. Normally an 18th
magnitude asteroid would be very obvious. Fortunately vdB 111 is a
rather bright reflection nebula. Though I likely lost its fainter outer
parts to sky conditions.


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

Rick



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