sgl processing competion

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Re: sgl processing competion

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BainthaBrakk wrote: Tue Sep 29, 2020 12:55 pm Thanks for the help Ivo!

I'll try to show you via a picture (Anne S) which I think have nice detail in the nebula and a tamed starfield with your picture as comparison:

o3(stars).jpg

The "wispy" O3 I'm rambling about is in the bottom-left corner of the nebula.. :P
I tried using the Entropy module a little, but I have not tried that before so I think I have to read up on that one. Thanks for the tip!

/Ulf
Ah. That OIII detail indeed should be easily brought out by weighing O-III higher for the purpose of luminance (you don't have to give up SHO coloring like many in that thread seem to feel they need to!).

As for "reduction" of the star field, it appears that this image is the result of a pretty crude application of a minimum filter ("Morphological Transform"). The exact same "stringy" look with the same pits, holes, artifacts and destruction of the filaments can be achieved by not using a star mask at all in the Shrink module (set iterations to 1, De-ringing to Off, Regularization to 0.00, Mode to Dim; which dumbs down the treatment to a simple minimum filter - at th every least I would de-select NGC6888). I would obviously not advocate trying to emulate this image if your goal is to do photography rather than creating "art"... E.g. this is close-up of that image is not something I would strive to emulate personally;
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Of course, it's a free world!
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Re: sgl processing competion

Post by BainthaBrakk »

Yeah, you are probably right. I really don't know what NGC6888 should look like. :P

But the starfield then? Here is a comparison between your pictures when it comes to stars:
Starfield.jpg
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Is there a way, without using starnet etc. to remove the tiny specks in the left hand picture, thus getting a less "busy" starfield?
It is subjective, as always, but I really prefer the stars in the right hand picture.

Thanks again!

/Ulf
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Re: sgl processing competion

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BainthaBrakk wrote: Wed Sep 30, 2020 4:33 pm Is there a way, without using starnet etc. to remove the tiny specks in the left hand picture, thus getting a less "busy" starfield?
Of course! Simply add those specks to any star mask you might want to use. The only (small) issue is that using more aggressive settings for the Auto Mask generator will likely see some of the nebulosity selected as well. If you're a perfectionist, you will want to de-select that manually (I actually didn't below). So, after Shrink and Life module application;
NewComposite.jpg
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It's all about using the (right) tools and tweaking to taste.
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Re: sgl processing competion

Post by BainthaBrakk »

Thanks Ivo, I'll try to tinker some more!

/Ulf
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Re: sgl processing competion

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admin wrote: Tue Sep 29, 2020 3:15 am ..
If O-III is of particular interest, have you tried Matrix in the Color module with dominant O-III coloring? (for example SHO 20SII+80Ha,20Ha+80OIII,100OIII), or tried compositing the SHO dataset with O-III weighted more highly for the synthetic luminance?
This has been a most interesting thread, so thanks to all who have contributed, but one thing I haven't quite got my head around is Ivo's comment above about increasing the weighting in the compose module. How is that achieved exactly? Is it by increasing (or perhaps decreasing?) the total exposure or does reweighting come elsewhere in the process altogether?
Skywatcher 190MN, astro modded Canon 700d, cls ccd, or Ha or Oiii filters, guided by OAG, ASI120, PHD2
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Re: sgl processing competion

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almcl wrote: Fri Oct 02, 2020 1:26 pm increasing the weighting in the compose module. How is that achieved exactly? Is it by increasing (or perhaps decreasing?) the total exposure or does reweighting come elsewhere in the process altogether?
When creating a synthetic luminance dataset for the purpose of working on your detail, the Compose module uses the exposure times you give it to create the correct blend.

From the docs;
The Red, Green and Blue buttons load a dataset in the "Red File", "Green File" and "Blue File" slots respectively. The "Red Total Exposure", "Green Total Exposure", "Blue Total Exposure" sliders determine the total exposure length in hours, minutes and seconds for each of the three slots. These values are used to create the correct weighted synthetic luminance dataset (at 1/3rd weighting of the "Lum Total Exposure"), in case the "Luminance, Color" composite mode is set to create a synthetic luminance from the loaded channels.
Setting Ha and S-II to 0, for example, will cause the weighting of OIII to be 100% for the purpose of luminance. E.g. the detail will consist of 100% O-III. Unless you change the "Luminance, Color" parameter, the coloring will still be SHO.

Any module that uses the color dataset as an input to manipulate the detail, in a sense, indeed does some further re-weighting. E.g. the Entropy module does this, as do the Red/Green/Blue Luminance Contribution parameters in the Develop module.
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Re: sgl processing competion

Post by almcl »

Thanks, Ivo, think I've got it now.

Back to pursuing that faint blue bulge at the lower left part of the nebula - yours looks wonderful - mine not quite as good yet but with a week of solid cloud in prospect this will be a good chance to improve!
Skywatcher 190MN, astro modded Canon 700d, cls ccd, or Ha or Oiii filters, guided by OAG, ASI120, PHD2
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Re: sgl processing competion

Post by Russ.Carpenter »

I hadn't been reading this thread until tonight. After 25 minutes of processing in StarTools, this was the result. Not perfect, but a pleasing image. Time to go to bed.

Russ
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Re: sgl processing competion

Post by Russ.Carpenter »

Last night I made an image of NGC 6888 that ruthlessly minimized the background. This morning I decided to move in the opposite direction, enlarging the field of view and making the background more prominent. Both images were processed in 25 minutes, plus or minus.

Neither image is nearly as good as Ivo could make, but they illustrate the versatility of StarTools.

Russ
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Re: sgl processing competion

Post by Burly »

Well done russ great work
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