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ASTRO: Barnard's Galaxy NGC 6822



 
 
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  #1  
Old June 30th 07, 08:01 PM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: Barnard's Galaxy NGC 6822

I've been fighting the color on this one a week now, time to give up.
Light fog rolled in during the middle of the red exposures. That spread
out the red light. Subtracting the haze weakened the red in the image
screwing up the color balance. Then increasing the red turned the
galaxy purple. I'm sure the Photoshop experts would have no problem but
it was beyond me. Many tries later this is the best I can do.

This is a low object for me, almost the same as M104. I was going to do
like I did with 104 and catch it in the gap in my Meridian Tree. But
one night seeing was super so I waited until it was clear of the tree,
but lower and got it all in one night avoiding flat bottomed stars of
M104. But then the "red fog" nailed me. Something has to go wrong or I
wouldn't get a good shot! Then blue was taken well into nautical
twilight so it is not good either adding to my processing woes.

Anyway, except for the lack of color in the main part of the galaxy,
this is likely as clear a shot of this low object I'll ever get so here
it is anyway. If I get a chance I'll redo the color frames binned 2x2
and without fog. But for now I'll post it this way.

14" LX200R @ f/10, L=4x10' binned 2x2, RGB = 2x10' binned 3x3,
STL-11000XM, Paramount ME

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

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  #2  
Old July 1st 07, 04:31 PM posted to alt.binaries.pictures.astro
Stefan Lilge
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Posts: 2,269
Default ASTRO: Barnard's Galaxy NGC 6822

Great picture Rick. I especially like the HII regions (supernova remnants?)
at the edge of the galaxy.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...
I've been fighting the color on this one a week now, time to give up.
Light fog rolled in during the middle of the red exposures. That spread
out the red light. Subtracting the haze weakened the red in the image
screwing up the color balance. Then increasing the red turned the
galaxy purple. I'm sure the Photoshop experts would have no problem but
it was beyond me. Many tries later this is the best I can do.

This is a low object for me, almost the same as M104. I was going to do
like I did with 104 and catch it in the gap in my Meridian Tree. But
one night seeing was super so I waited until it was clear of the tree,
but lower and got it all in one night avoiding flat bottomed stars of
M104. But then the "red fog" nailed me. Something has to go wrong or I
wouldn't get a good shot! Then blue was taken well into nautical
twilight so it is not good either adding to my processing woes.

Anyway, except for the lack of color in the main part of the galaxy,
this is likely as clear a shot of this low object I'll ever get so here
it is anyway. If I get a chance I'll redo the color frames binned 2x2
and without fog. But for now I'll post it this way.

14" LX200R @ f/10, L=4x10' binned 2x2, RGB = 2x10' binned 3x3,
STL-11000XM, Paramount ME

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".


  #3  
Old July 1st 07, 06:37 PM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: Barnard's Galaxy NGC 6822

I think most, if not all, are huge HII regions. Each has a cluster of
stars in it. Think they are huge bubbles blown by the clusters. Though
a few of the biggest members likely went super nova and are helping
make the bubbles. If my calculations are right the big one to the North
west (upper right) is about 500 light years across! Those stars in the
cluster have to be super massive to light up a bubble at that distance!
Make something like the Rosette look puny by comparison.

Two have been photographed by Hubble.

Hubble X is the bright spot at the upper edge of the galaxy just left of
center. A large bubble extends down from it but it appears Hubble X is
just the bright blob. Resolution is too poor to show the stars separate
from the Hydrogen and their blue dominates making it come out white
rather than pink.
http://apod.nasa.gov/apod/ap010216.html

Hubble V to the right of Hubble X shows a hint of pink but again the
stars so dominate little pink is seen, it too is at the "top" of the
galaxy as far right of center as Hubble X was left. The only way I
figured this out was to put the designation Hubble X and V into the DSS
search engine using NED as the source and setting the size to about 5
minutes so finding the center was easy then redoing it at a larger size
so I could see where I was looking. Hubble's shot of Hubble V is at
http://apod.nasa.gov/apod/ap011225.html

For lurkers not into the DSS plates here's the page I used.
http://stdatu.stsci.edu/cgi-bin/dss_form/ Be sure to select NED for the
search. Default Simbad doesn't know them by that name. Then when
viewing the plate chose GIF and the size unless you want to wait for the
much larger FITS file to download.

I doubt Hubble's orientation is the same as mine and the scale so large
compared to my resolution I can't recognize much in my shot. Obviously,
the one of Hubble X is taken with narrow band filters so is false color.

Rick


Stefan Lilge wrote:

Great picture Rick. I especially like the HII regions (supernova
remnants?) at the edge of the galaxy.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

I've been fighting the color on this one a week now, time to give up.
Light fog rolled in during the middle of the red exposures. That spread
out the red light. Subtracting the haze weakened the red in the image
screwing up the color balance. Then increasing the red turned the
galaxy purple. I'm sure the Photoshop experts would have no problem but
it was beyond me. Many tries later this is the best I can do.

This is a low object for me, almost the same as M104. I was going to do
like I did with 104 and catch it in the gap in my Meridian Tree. But
one night seeing was super so I waited until it was clear of the tree,
but lower and got it all in one night avoiding flat bottomed stars of
M104. But then the "red fog" nailed me. Something has to go wrong or I
wouldn't get a good shot! Then blue was taken well into nautical
twilight so it is not good either adding to my processing woes.

Anyway, except for the lack of color in the main part of the galaxy,
this is likely as clear a shot of this low object I'll ever get so here
it is anyway. If I get a chance I'll redo the color frames binned 2x2
and without fog. But for now I'll post it this way.

14" LX200R @ f/10, L=4x10' binned 2x2, RGB = 2x10' binned 3x3,
STL-11000XM, Paramount ME

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".



  #4  
Old July 4th 07, 02:44 AM posted to alt.binaries.pictures.astro
George Normandin[_1_]
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Posts: 1,022
Default ASTRO: Barnard's Galaxy NGC 6822

"Rick Johnson" wrote
....
I've been fighting the color on this one a week now, time to give up.
Light fog rolled in during the middle of the red exposures.......


It looks great to me Rick! ....but then I'm blue/green color blind.

George N


 




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