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Please share with a newbie: What is your processing workflow in 2025?

Luc Coiffier DeepSkyStacker (DSS) Steffen Hirtle GraXpert Processing Deep Sky
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thornhale avatar
thornhale avatar
Hi community,

As a relative newbie, I am really trying to improve my processing this year. I am trying to do so relying largely still on free or affordable tools.

For reference, this was my old workflow:

1.) Stack in Deepskystacker.
2.) Stretch the image in GIMP.
3.) Do curve contrast adjustments in GIMP.
4.) Adjust the contrast in GIMP.
5.) Crop in GIMP.

Starting this year then, I tried to improve the above basic workflow which now looks like this:

1.) Stack in Siril
2.) Crop in GraXpert.
3.) Gradient removal in GraXpert.
4.) Green Noise removal in Siril
5.) Denoising in GraXpert
6.) Stretching in Sirl
7.) Colorimetric color adjustment in Siril.
8.) Contrast curve adjustment in GIMP.
9.) Deconvolution in Cosmic Clarity or just sharpening in GIMP

Steps 1-8 were adapted by watching a simplified tutorial video that Cuiv, the lazy Geek, shared on YouTube. That said, I am not sure that what I am doing is the right thing. I am certain there are better ways to do this. I have not drizzled, or binned anything yet knowingly. Seestar S50 may actually drizzle because I have noticed the subs jumping around a bit. I also can't seem to figure out how to make starnett ++ work in Siril to proccess the background separately from the stars. There are many things I still want to learn.


So please share how you are processing the images in 2025!
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Tony Gondola avatar
Tony Gondola avatar
I'm am going to give you a workflow but keep in mind that it really isn't a static thing. The tools and sequencing will vary depending on the data and the goal. Also, I am going to use general terms for the steps so you can adapt whatever tools you have access to. This is for OSC…


Stack using background extraction for every frame.

Visually inspect the stack as the first step in the culling process.

Re-stack using only the best frames by telling the stack engine what your upper limits for FWHM and roundness are.

Sharpen the stacked result.

Remove the stars (optional).

Preliminary stretch of the starless image.

extract any remaining gradient.

Remove green noise.

Refine the stretch and the image using a photo editor. This can involve dozens of operations and will be different with each image. The bulk of the work is often done here.

Stretch the stars only image

Recombine the starless and stars only image

Denoise.

Crop.

Create final 16 bit tiff and 8 bit JPG.
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Dan Burns avatar
Dan Burns avatar
I am still learning too but one thing I started doing recently was processing nebula and stars separately. I am not sure how to get Starnett to work with Siril, but I know you can use it by itself to create a starless image. I load it with the original image into Photoshop as layers, select both, then create a difference layer. That gives a star only image. You can then process that separately from the image with just the nebula. I am pretty sure Gimp can do this too. Even better is to create a separate image with shorter exposures for just the stars.
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Tony Gondola avatar
Tony Gondola avatar
You can remove stars using Starnet directly in Siril. It's in the menu, just go into preferences and give it the path to the Starnet.exe file.
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Taylor C avatar
Taylor C avatar
Dan Burns:
I am still learning too but one thing I started doing recently was processing nebula and stars separately. I am not sure how to get Starnett to work with Siril, but I know you can use it by itself to create a starless image. I load it with the original image into Photoshop as layers, select both, then create a difference layer. That gives a star only image. You can then process that separately from the image with just the nebula. I am pretty sure Gimp can do this too. Even better is to create a separate image with shorter exposures for just the stars.

You can add starnet to siril in the settings, open your settings and there will be a section for scripts I believe (not in front of my pc at the moment) in that section you’ll see starnet with a little box with 3 dots inside it. If you click that box it should bring up your file explorer and you can navigate to wherever you have starnet saved to, highlight the actual .exe file and click open in the bottom right corner. That should allow you to run starnet in siril. I hope this helps, you wouldn’t believe how long it took me to figure it out. Also, make sure you download the script version of starnet if you’re wanting to run it that way. 
Clear skies!
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Médéric Hébert avatar
Médéric Hébert avatar
Still a newbie, but mine looks like this:
  • Stack in Sirilic/Siril
  • Either crop in Siril if RGB or each channel seperatly in Gimp if SHO+RGB stars or LRGB (I only do mono)
  • Gradiant removal in Siril
  • Asinh strech followed by histogram stretchs
  • Green noise removal if SHO / photometric color correction if RGB
  • Remove stars sith Starnet (from within Siril)
  • Move over to Gimp for final stretching, color saturation, Stars recombination, final crop, denoising and sharpening (order may vary depending on target).
  • Export to .jpg
  • Post on Astrobin / email it to friends and family that want to see them.


As for seperating nebulosity from the stars in Gimp, I just substract the starless image from the regular one, the make a new layer from visible.
Also found that duplicating the nebulosity layer and turning it into a high pass filter that get overlayed increase sharpness nicely.
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Manu Oliva avatar
Manu Oliva avatar
Monty Chandler avatar
Monty Chandler avatar
Fundamentally for OSC

Image calibration 
Cosmetic correction 
Debayer
blink
star alignment 
local normalization 
image integration 
dynamic crop 
image solution 
background extraction 
blurx correction only
spcc
blurx
noisex
star exterminator 
ghs the star image
ghs the starless image
various crvs adjustments 
blend the stars back in


cheers
thornhale avatar
thornhale avatar
Thank you all! Your posts have made me improve my processing in just the past few days!

I learned to include the asinh transformation step into my workflow.
I also revisited the topic of starnet++ not working for star separation, and made it work. This has allowed me to process the stars and the dso separately from each other.
It made me discover how to use pixel math so that I can bring stars bag in again at lesser intensities.

Thanks to you input, M101 went from:

https://www.astrobin.com/gn893m/

To this (with different levels of post processing in the revisions):

https://www.astrobin.com/ijcjym/D/

The wonderful thing is that I spent 0 extra dollars on new equipment or otherwise to improve the image. I had no idea how big of a difference better post-processing techniques can make, and I am sure that I have just scratched the surface and that there still much I have to learn.

Please continue sharing what you are doing!
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Tony Gondola avatar
Tony Gondola avatar
That's a great improvement so you are well on your way. My main advice at this point is keep on experimenting and learn the tools you have, inside out. Do a lot of testing and A/B comparisons. Keep your eyes out for new tools and techniques. Your personal workflow should not be a static process but one that evolves over time. Keep looking for ways to make those little improvements that add up over time.
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Mikolaj Wadowski avatar
Mikolaj Wadowski avatar
Mine looks something like this:

1. Crop
2. Gradient extraction
3. Color calibration
4. Sharpening
5. Noise reduction
6. Star extraction
7. Stretching (both starless and star-only)
8. Saturation and other small adjustments
9. Screen the stars back.

A couple of notes on improving any workflow:
- Sharpen before noise reduction
- Color calibration must be done on barely processed data - before any stretching, noise reduction, and non-linear color adjustments
- Don't use SCNR/Green noise removal. Definitely don't use it as a means of "calibrating" the colors (i.e. removing the initial color cast which is often green). A proper color calibration will also take care of this without ruining the color data and making the image bi-color in the process. In 99% of cases, a simple destretching or curve adjustment for the green channel will get rid of a green cast if it's still there after color calibration.

Also, I recommend downloading the newest Siril dev version. There are a ton of new features that will improve your results further.
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Tony Gondola avatar
Tony Gondola avatar
Mikolaj Wadowski:
Mine looks something like this:

1. Crop
2. Gradient extraction
3. Color calibration
4. Sharpening
5. Noise reduction
6. Star extraction
7. Stretching (both starless and star-only)
8. Saturation and other small adjustments
9. Screen the stars back.

A couple of notes on improving any workflow:
- Sharpen before noise reduction
- Color calibration must be done on barely processed data - before any stretching, noise reduction, and non-linear color adjustments
- Don't use SCNR/Green noise removal. Definitely don't use it as a means of "calibrating" the colors (i.e. removing the initial color cast which is often green). A proper color calibration will also take care of this without ruining the color data and making the image bi-color in the process. In 99% of cases, a simple destretching or curve adjustment for the green channel will get rid of a green cast if it's still there after color calibration.

Also, I recommend downloading the newest Siril dev version. There are a ton of new features that will improve your results further.

Where do I find the link for the dev version?
Mikolaj Wadowski avatar
Mikolaj Wadowski avatar
It's on the gitlab repository.
Go to Build > Pipelines and look for one that targets the 'master' branch. Download the latest one that passed.
Link for quick access
Tony Gondola avatar
Tony Gondola avatar
Mikolaj Wadowski:
It's on the gitlab repository.
Go to Build > Pipelines and look for one that targets the 'master' branch. Download the latest one that passed.
Link for quick access

THanks!
Tony Gondola avatar
Tony Gondola avatar
Mikolaj Wadowski:
It's on the gitlab repository.
Go to Build > Pipelines and look for one that targets the 'master' branch. Download the latest one that passed.
Link for quick access

Just one more question: I've download and extracted the files. How do I build the application in Windows?