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A Vanilla M101

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#1 joydeepb

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Posted 23 April 2024 - 01:06 PM

This project started out as "oh good, a clear night in three weeks, let's just see if the rig still works after re-assembly after the eclipse!"
I call it a "Vanilla M101" since it's a solid B+ IMO. Not going to win any awards with the lack of reach and detail on the galaxy, and the DR is not the greatest, especially with just 7 hours, but it's relatively clean, and unassuming. :-)
 
Full image (click to go to Astrobin page):
med_gallery_480324_25341_1498033.jpg

And a crop of M101:
med_gallery_480324_25341_39599.png

Comments and critiques are welcome!
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#2 EPinNC

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Posted 23 April 2024 - 01:13 PM

That's a nice image!  I'll bet there is more color there that could be brought out in processing, so keep all your files on this one.  All those faint little galaxies in the background suggest (to me) that you've got good-quality data.  How are you processing it?  (I see you have Siril, but what post-stacking procedures are you using?)


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#3 joydeepb

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Posted 23 April 2024 - 02:00 PM

That's a nice image!  I'll bet there is more color there that could be brought out in processing, so keep all your files on this one.  All those faint little galaxies in the background suggest (to me) that you've got good-quality data.  How are you processing it?  (I see you have Siril, but what post-stacking procedures are you using?)


Thanks, EP!

My workflow is (Siril):
- Preprocess
- Banding reduction
- DBE with high (~0.5) smoothing factor to remove global gradients
- DBE with low (~0.2-0.3) smoothing factor to remove persistent local gradients
- Remove green noise
- DBE with high (~0.5) smoothing factor to restore most of the color modified by green noise removal
- PCC
- Starnet starless + mask
- Starless: GHS xN times to taste to bring out galaxy arm details
- Recombine with stars (stretch stars with arcsinh to taste)
- Export to 32-bit TIFF
- [Photoshop] Adobe Raw: curves, vibrancy + contrast, color noise reduction
- [Photoshop] RC NoiseX

Yup, definitely keeping this around to add more data later! :-)
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#4 Navy Chief

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Posted 23 April 2024 - 02:18 PM

Nice image, agree that with the detail in the smaller galaxies that there is good data there. I am insanely jealous that you had an actual clear night, things have not been aligning for me between weather and personal obligations. 


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#5 Borodog

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Posted 23 April 2024 - 02:38 PM

Care to share your unprocessed raw stack with the peanut gallery?


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#6 rj144

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Posted 23 April 2024 - 04:09 PM

Nice pic.

 

What's your Bortle zone?



#7 rj144

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Posted 23 April 2024 - 04:11 PM

Thanks, EP!

My workflow is (Siril):
- Preprocess
- Banding reduction
- DBE with high (~0.5) smoothing factor to remove global gradients
- DBE with low (~0.2-0.3) smoothing factor to remove persistent local gradients
- Remove green noise
- DBE with high (~0.5) smoothing factor to restore most of the color modified by green noise removal
- PCC
- Starnet starless + mask
- Starless: GHS xN times to taste to bring out galaxy arm details
- Recombine with stars (stretch stars with arcsinh to taste)
- Export to 32-bit TIFF
- [Photoshop] Adobe Raw: curves, vibrancy + contrast, color noise reduction
- [Photoshop] RC NoiseX

Yup, definitely keeping this around to add more data later! :-)

Try without PCC and do a manual color calibration.  PCC is hit and miss for me... also try an arcsinh stretch before GHS.


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#8 BQ Octantis

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Posted 23 April 2024 - 04:58 PM

... also try an arcsinh stretch before GHS.

Vidrazor recently showed this was unnecessary. Just do the GHT and follow-up with a GHT saturation stretch. This results in a much fuller utilization of the sRGB gamut…

 

https://www.cloudyni...ost/?p=13393691

 

BQ


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#9 joydeepb

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Posted 23 April 2024 - 08:15 PM

Nice image, agree that with the detail in the smaller galaxies that there is good data there. I am insanely jealous that you had an actual clear night, things have not been aligning for me between weather and personal obligations.


Thanks! For bit it was looking like we'd never see a clear sky again in Austin TBH.
 

Care to share your unprocessed raw stack with the peanut gallery?


Sure, here you go! https://drive.google...?usp=drive_link
 

Nice pic.
 
What's your Bortle zone?

Thanks! I'm in B8/9: Austin, TX. About 3 miles from downtown.
 
 

Try without PCC and do a manual color calibration.  PCC is hit and miss for me... also try an arcsinh stretch before GHS.

PCC: true, I've seen it to be variable, too, indeed.
 
 

Vidrazor recently showed this was unnecessary. Just do the GHT and follow-up with a GHT saturation stretch. This results in a much fuller utilization of the sRGB gamut…
 

https://www.cloudyni...ost/?p=13393691

 
BQ

Oh, that's interesting - thanks for the pointer, will have to dig into more detail.
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#10 Sheridan

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Posted 24 April 2024 - 04:25 AM

I feel the same way about Houston seems like a river of clouds ☁️


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#11 rj144

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Posted 24 April 2024 - 10:19 AM

I feel the same way about Houston seems like a river of clouds ☁️

I've had my best stretch in weeks the last few nights.  Of course, it's a full moon though.  Grrrrrrrrrrrrrrrrr....


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#12 BQ Octantis

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Posted 24 April 2024 - 04:00 PM

Oh, that's interesting - thanks for the pointer, will have to dig into more detail.

Another thing you might consider to improve the stretch: insert a black point-only Histogram Transformation right after PCC. This will remove the colorless bias, which will (1) provide a more contrasty result and (2) provide an immediate color boost.

 

BQ




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