ASTRO: LDN 673 Into the murk

LDN 673 is a large complex of dark clouds in Aquila on the eastern edge
of the dark rift in the Milky way that passes through the constellation.
Unfortunately transparency was putrid this night (I know I sound like
a broken record) so the image is severely underexposed. Blue is
compromised by moonlight so my color is suspect and likely too red in
fainter regions. Another for the reshoot list for next year.

The nebula at the top right is the reflection nebula GN 19.18.0 and
surrounds the YSO candidate (Young Stellar Object) 2MASS
J19201949+1121544. I've seen it called RNO 109 but SIMBAD puts that
just out of my image to the upper right of the object. It might be the
position is in error, I don't know why the discrepancy. Near the bottom
on the right is the HH32 complex. It is around the V Orionis type star,
V1352 Aql. SIMBAD also shows a T Tauri star only 0.25" south identified
as EM* AS 353A. The EM* indicates it is an emission line star. Are
these two separate objects or two different catalog entries for the same
object? They lie within the error bar for the positions of each. The
first is listed as being of spectral type Cn indicating a carbon star
while the latter is K2. Note the very red emission object to the west
(right) of this possible pair of stars. The position given for these
two stars is actually between the two stars in my image which are
separated by about 2" of arc not 0.25". Checking the magnitudes of the
stars the K2 star has a blue magnitude of 13.5 and a V (green) magnitude
of 12.5 so is slightly red. Carbon stars are normally very red yet the
carbon star's B and V magnitudes are 11.5 and 12 respectively indicating
a blue star! Now I'm really confused.

The bright blue star on the lower right is 8th magntitue SAO 104730 an
A0 star so some six times dimmer than a 6th magnitude star considered
the limit of human vision from a dark skies site (probably conservative
for an experienced observer but reasonable to the casual sky gazer with
untrained night vision.

A bit right and just below center line a very blue star that stands out
from all the red. It is the white dwarf star GD 218 at magnitude 16.

This is the last image for July. While conditions for this one were
poor they were even worse the rest of the month. No more imaging was
possible until August.

14" LX200R @ f/10, L=4x10' RGB=2x10' (all under poor to very poor
conditions), STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

Rick,

lots of interesting stuff in your image, especially the Herbig-Haro objects.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

LDN 673 is a large complex of dark clouds in Aquila on the eastern edge
of the dark rift in the Milky way that passes through the constellation.
Unfortunately transparency was putrid this night (I know I sound like
a broken record) so the image is severely underexposed. Blue is
compromised by moonlight so my color is suspect and likely too red in
fainter regions. Another for the reshoot list for next year.

The nebula at the top right is the reflection nebula GN 19.18.0 and
surrounds the YSO candidate (Young Stellar Object) 2MASS
J19201949+1121544. I've seen it called RNO 109 but SIMBAD puts that
just out of my image to the upper right of the object. It might be the
position is in error, I don't know why the discrepancy. Near the bottom
on the right is the HH32 complex. It is around the V Orionis type star,
V1352 Aql. SIMBAD also shows a T Tauri star only 0.25" south identified
as EM* AS 353A. The EM* indicates it is an emission line star. Are
these two separate objects or two different catalog entries for the same
object? They lie within the error bar for the positions of each. The
first is listed as being of spectral type Cn indicating a carbon star
while the latter is K2. Note the very red emission object to the west
(right) of this possible pair of stars. The position given for these
two stars is actually between the two stars in my image which are
separated by about 2" of arc not 0.25". Checking the magnitudes of the
stars the K2 star has a blue magnitude of 13.5 and a V (green) magnitude
of 12.5 so is slightly red. Carbon stars are normally very red yet the
carbon star's B and V magnitudes are 11.5 and 12 respectively indicating
a blue star! Now I'm really confused.

The bright blue star on the lower right is 8th magntitue SAO 104730 an
A0 star so some six times dimmer than a 6th magnitude star considered
the limit of human vision from a dark skies site (probably conservative
for an experienced observer but reasonable to the casual sky gazer with
untrained night vision.

A bit right and just below center line a very blue star that stands out
from all the red. It is the white dwarf star GD 218 at magnitude 16.

This is the last image for July. While conditions for this one were
poor they were even worse the rest of the month. No more imaging was
possible until August.

14" LX200R @ f/10, L=4x10' RGB=2x10' (all under poor to very poor
conditions), STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net