Thread: ASTRO: vdB 111
View Single Post
  #1  
Old April 17th 13, 08:20 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
external usenet poster
 
Posts: 3,085
Default ASTRO: vdB 111

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
--
Prefix is correct. Domain is arvig dot net

Attached Thumbnails
Click image for larger version

Name:	VDB111L4X10RGB2X10.JPG
Views:	296
Size:	449.9 KB
ID:	4576  Click image for larger version

Name:	VDB111L4X10RGB2X10-67.JPG
Views:	207
Size:	263.4 KB
ID:	4577