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PN NGC 6905 with only 800mm

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#1 hobbyknipser

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Posted 22 July 2021 - 03:31 PM

Hi,

 

a few nights ago I took a shot at the PN NGC 6905 with my 8" f/4 Newtonian and a modified Canon 77d.

In spite of bad mount tracking, the telescope was not calibrated and the coma corrector not exactly in the middle of the focuser, I stacked 360x20 sec with DSS and made the best of these problems (1. image).

Hoping for a better resolution, I stacked only some 48x20 sec crops manually with fitswork and sharpened the result (2. image).

Next time I will use my C9.25 for this little PN.

 

NGC_6905_364x20s_180721_alle1_aus_rg.jpg

 

 

 

cheers

Andreas

 

 

 

 


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#2 hobbyknipser

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Posted 22 July 2021 - 03:32 PM

...2. image:

 

Zielbild_48x20sec_180721_2rg.jpg

 

greetings

Andreas

 


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#3 vidrazor

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Posted 25 July 2021 - 06:59 PM

...2. image:

greetings

Andreas

That's better I think. I ran your first render through Siril's deconvolver. It brought up detail but not surprisingly also noise. I color corrected it because your balance looked green-yellow, removed the noise in the skies but I left in in the luminosity data. Better than before perhaps but this one you did here is a little better I think.
 

Attached Thumbnails

  • NGC 6905-Siril.jpg

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#4 hobbyknipser

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Posted 26 July 2021 - 01:29 PM

Hi, vidrazor,

 

Thanks for your improvement of my image! smile.gif

 

Yes, your colors are better and the background darker. I have sharpened the PN as much as senseful.

How did you color-correct it: with the photometric color calibration...and how did you remove the noise?

 

greetings

Andreas



#5 vidrazor

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Posted 26 July 2021 - 07:05 PM

Hi, vidrazor,

Thanks for your improvement of my image! smile.gif

Yes, your colors are better and the background darker. I have sharpened the PN as much as senseful.

How did you color-correct it: with the photometric color calibration...and how did you remove the noise?

greetings

Andreas

For the sky noise reduction, I made a star and target mask by running a copy of the render on a separate layer through dust & scratches and creating a difference calculation between the D&S layer and the original data that had been passed through Siril's deconvolver. I used the smoothed D&S layer for the skies using the star & target mask along with the layer luminosity mask inherent in the Photoshop layers. This allowed me to dial the smoothed D&S sky in to blend with the luminosity data so you don't lose any detail. I color corrected the image in Photoshop using reference images online with levels, hue & sat, and selective color adjustment layers.

 

I gave a shot with a similar set of processes on your second shot.
 

Attached Thumbnails

  • NGC 6905_A-B.jpg

Edited by vidrazor, 26 July 2021 - 08:16 PM.


#6 hobbyknipser

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Posted Yesterday, 12:35 PM

Hi, vidrazor,

 

many thanks for the further information!

 

cheers

Andreas




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