From one of the best skyes of Argentina, in San Rafael, province of Mendoza.
I was in a star party and only had with me the camera and a little tripode, then, I tried a cuople of image.
This is a single image unguied, and ofcourse the stars are lines, but when resampled is almost imperseptible.
Canon 5DIII - ISO 12800 - Exposure: 30 seconds - F/D 6,44 - Focal Length 24 mm
As I do not have masters for this ISO, I integrated 50 bias of ISO 6400 to generate the MaserBias and use a single 20 minutes darks to calibrate as I have a line that need to be corrected with a dark.
Debayer of te calibrated image and correct some Cold and Hot pixels
There were needed two DBE to correct the gradients. (I do not use flats for calibration)
Generate a preview representative of the background to be used as Reference Image in Background Neutralization Tool
Generate a preview of the main part of the galaxy to be used as Reference Image for White Reference in Color Calibration and the same preview as before to be used as Reference Image for Background Reference
Now the key cuestion here is generate a mask that allow to process the sky without afecting the mountains and viceversa.
For that I clone the image and apply consecutivelly Morfological transformations and smoothnees with ATWT until have a good diferenciation between sky and mountains that allow range mask to generate what I am looking for.
Now I will work protecting the mountains. First apply the formula to elimiante darks holes.
Transfer STF to the HT tool and apply
Noise reducction: to green
Chrominance noise reduction in big scales
Saturation with CurvesTransformation
Noise reduction in one pixel layer using MultiscaleMedianTransform tool
Chrominance nose reduction in layers from two to eight pixels
A little more contrast with ATWT
Curves to correct colors (a and b)
Exponential transformation to smoothnees the background
Now I need a more located chrominance noise reduction, for that I will generate a mask that protect at the same time the mountains and the brigh part of the sky.
Extract Luminance, invert and apply curves and ATWT to smoth a little
Then, with PixelMath add the luminance and the previous RangeMask
Now apply chrominance noise reduction in the background
Protecting now the sky with the first range mask, apply HT to the mountains (Transfer the STF to the HT tool)
Reduce red in the sky protecting the mountains.
Noise reduction to smooth the background using ACDNR
Rotate 90° Counter-Clockwise and resample