[RCC] How to improve my Image of the Wizard Nebula Requests for constructive critique · Johannes Möslein · ... · 5 · 589 · 3

This topic contains a poll.
Biggest problem with the Image?
Bad Data (Moon, clouds)
Not enough Data
Stretching
Processing in general
Equipment
Other
Joo_Astro 1.91
...
· 
Hi,
I took this Image of the Wizard Nebula. I took 20h of Data because I wanted to get a good picture, but I'm not that happy with the result. Don't get me wrong, I like it, but still I want to improve.

The scope was probably a little bit out of collimation during that time.
I think the moon and some thin clouds were up too, so that is probably the biggest problem.
Here are the masters if anyone wants to try a quick edit. ;)

I tried editing it differently many times, but the best I achieved is the one I uploaded. So please give me some tips on how to improve it.
I can't remember the exact workflow, but generally I do something like this (Pixinsight):
  • StarAlignment
  • DynamicCrop
  • ChannelCombination RGB
  • StarXTerminator on RGB, L
  • DBE on L (Normalize checked)
  • Same DBE process on RGB
  • Add Stars back in RGB, L
  • SPCC on RGB
  • BlurXTerminator on RGB, L
  • NoiseXTerminator on RGB, L
  • StarXTerminator on RGB, L
  • GHS on RGB, L
  • Sharpen L a bit
  • LRGBCombination
  • ArcsinhStretch RGB_stars
  • Add RGB_stars back in
  • Final touches to color, contrast etc.


Thank you for reading .



NGC 7380-The Wizard Nebula
Like
andreatax 7.76
...
· 
·  1 like
Don't know where to beging (and apologies for being blunt)...

1. Poorly calibrated (there are a host of hot pixels spread in the picture) .
2. Overstretched (you haven't got the dynamics for that).
3. Overprocessed. And in light of the poor field correction this should have been avoided from the start.
4. Overly contrasty (and too dark) with poor color dynamics.
5. Overly de-noised (blotchy aspect).
Like
Joo_Astro 1.91
...
· 
andrea tasselli:
Don't know where to beging (and apologies for being blunt)...

1. Poorly calibrated (there are a host of hot pixels spread in the picture) .
2. Overstretched (you haven't got the dynamics for that).
3. Overprocessed. And in light of the poor field correction this should have been avoided from the start.
4. Overly contrasty (and too dark) with poor color dynamics.
5. Overly de-noised (blotchy aspect).

Well thanks for the very…direct feedback. I’ll start over and try a soft edit once I get home.
Like
churmey 1.51
...
· 
·  4 likes
Hi Johannes,

You have some wonderful data here and you should be proud of this Aquisition. However, it is not without issues. Something very bazaar is going on with your stars that I don't understand. It's like they aren't aligning properly and they appear to be oversharpened. I suspect that it's an alignment issue and you are suffering some form of odd abrasion during registration/stacking. Could be a filter issue or optic issue...I'm not sure, therefore I did not emphasize the stars during my edit. Having said that, your background luminance data is spectacular. 

Keep in mind that we are all on a processing learning curve so don't be discouraged. You are asking the right questions. My workflow for this edit is as follows (I only worked with your RGB data). 

1) I re-registered your RGB files as they didn't appear to be properly registered
2) I PI linear fit the RGB files
3) I separated the stars from the background 
4) I ran a Dynamic Background Extraction on the background Luminance
5) I color calibrated the background luminance data
6) I saved the initial "more red" version and saved the color calibrated version. 
7) I blended the two
8) I added the stars back in

Things I noted that I might suggest to you. 

1) Determine your star issue
2) Be subtle on your data (try not to over sharpen or over noise reduce)
3) Learn about Linear Fitting Channels and Dynamic Background Extraction techniques) 
4) Learn best methods for separating your stars from your background. 
5) Learn best methods for color correcting. 
6) I noticed that you had a lot of variable framing in your stack. Try and keep your centering/guiding centered and consistent, and dither. 

Again, there is a lot here to be proud of and congratulations on some very nice luminance data. Here is my 15 minute edit that I hope can display how good this background data was. Good luck and keep up the good work

WIZZARD PNG.png
Like
Joo_Astro 1.91
...
· 
Hi Johannes,

You have some wonderful data here and you should be proud of this Aquisition. However, it is not without issues. Something very bazaar is going on with your stars that I don't understand. It's like they aren't aligning properly and they appear to be oversharpened. I suspect that it's an alignment issue and you are suffering some form of odd abrasion during registration/stacking. Could be a filter issue or optic issue...I'm not sure, therefore I did not emphasize the stars during my edit. Having said that, your background luminance data is spectacular. 

Keep in mind that we are all on a processing learning curve so don't be discouraged. You are asking the right questions. My workflow for this edit is as follows (I only worked with your RGB data). 

1) I re-registered your RGB files as they didn't appear to be properly registered
2) I PI linear fit the RGB files
3) I separated the stars from the background 
4) I ran a Dynamic Background Extraction on the background Luminance
5) I color calibrated the background luminance data
6) I saved the initial "more red" version and saved the color calibrated version. 
7) I blended the two
8) I added the stars back in

Things I noted that I might suggest to you. 

1) Determine your star issue
2) Be subtle on your data (try not to over sharpen or over noise reduce)
3) Learn about Linear Fitting Channels and Dynamic Background Extraction techniques) 
4) Learn best methods for separating your stars from your background. 
5) Learn best methods for color correcting. 
6) I noticed that you had a lot of variable framing in your stack. Try and keep your centering/guiding centered and consistent, and dither. 

Again, there is a lot here to be proud of and congratulations on some very nice luminance data. Here is my 15 minute edit that I hope can display how good this background data was. Good luck and keep up the good work

WIZZARD PNG.png

Thank you for your feedback.

That looks pretty nice, I’ll look what I can achieve later with a less aggressive edit, as Andrea suggested too. 

I agree, there is some issue with the stars I haven’t found the source of. Things aren’t aligning correctly, and when using something like BlurX, it becomes even worse. I blamed it on the RC being out of collimation, but I’ll try to repeat stacking data to see if that changes things.

You’re right about the color, I played with the different sliders and liked the dramatic colors, but of course that’s not correct.

Thank you for the tips, I’ll keep them in mind.
Like
Joo_Astro 1.91
...
· 
So here's just a quick update for closure:

I tried some soft editing, and the result was quite good. So I'll just practice my processing techniques some more.

Afterwards, I took some time to look through the Data, and found some Problems.
  • The Data was captured before my second try on Collimation, and the subs show that...newer Data looks a lot better, especially on the stars.
  • I used ASTAP to inspect some subs, and it gave me a tilt value of...40%. 

I feel dumb for not checking the Data earlier, but I guess you always learn something new with this great hobby.
Like
 
Register or login to create to post a reply.