Hello!

Finally I have completed my first "LRGB processing workflow" in PixInsight for the M31-Andromeda galaxy project! 
I needed really a lot of effort in order to study in-depth a right approach, and I have experimented different workflows during previous months, in order to understand better the impact of each single step.
In order to accomplish the result, I approached the workflow as in the following steps here described for the sake of completeness and sharing purpose (after the "WeightedBatchPreProcessing" praparation phase):
- in the linear phase with operations of: "Stars alignment" (in order to reduce a little the chromatic aberration upon stars) "Linear Fit", "Dynamic Background Extraction" and a first "Background Neutralization";
- extraction of a synthetic luminance "CIE L* component" in order to do: "setting of proper RGB workspace", "Deconvolution", "Sharpening" with "MultiscaleLinearTransform - MLT", "Unsharp Mask" and "HDRMT" techniques after a stretch with "Histogram Transformation" and the "Exponential" stretch utility; I combined the luminance sharped then with "PixelMath";
- extraction of the "RGB component" (after the "SpectroPhotometricColorCalibration" and the "Background Neutralization") and stretch with "Histogram Tranformation"
and the "hyperbolical ARCSIN" stretching function (also with a starless images processing phase in order to highlights as  better as possible all the previous calibrated colors).
Then, I finally ended with the "LRGB re-combination" with proper weights and further steps  of "Curve Tranformations", "Color Saturation" and "Noise Reduction" (both with "MLT" and "TGV" de-noise). 

The ARCSINH stretching function in the starless processing phase (I adopted "Starnet") allowed me to emphasize a bit the color of HII regions (the most prominent ones - I'll try soon to add also H-alpha data during this year!).

It took me really several days/lot of hours of effort (it is really a work the post-processing phase) to accomplish all the project, the latter allowing me to consolidate a first complete workflow in PixInsight. 
I used also Photoshop for the "selective color" approach for a little emphasize of the already calibrated colors with PixInsight, together with the "Astronomy Tools Action set".
After months of preparation and an intense full week of post-processing, I'm really enthusiast to share here the result.

Instruments of de-noise (like "MLT" , "TGV" , "SCNR" and even "Astronomy Tool") have been also used as above mentioned, but I maintained a bit of balance.

I imaged the Andromeda galaxy for four nights between September and October 2022, with the L-PRO filter and (as a new entry) a field flattener (I calculated properly its backfocus with spacers).
The OCS camera has been set to T = 0 °C.

The Andromeda galaxy is really fascinating, by looking at the structures visible along the edge is impressive the sensation of all matters involved in its gravitational field.
With the HDRMT technique also the structures very near the center appeared also more visible (and especially in the luminance b/w starless image the tri-dimensional sensation is really really strong).
I appreciate also the NGC206 star cloud, really bright, trasmitting us the dynamicity of the stars formation regions. 

I really enjoyed the journey in the post-processing giving me a wonderful emotion when I reached the result I had just n my dream (from home). My Bortle scale is class "5".
Again, in order to proper find the angle orientation during the multiple nights of the astrophotography sessions, I used the home-made paper goniometric scale (already described in the gallery) together with "APT".

I really appreciate any comment or suggestion,
all the best and CS,
Davide Mascoli.