Shot taken during my 4 days stay with my Airbus DS Club Astro mates, in the Southwestern France area sometimes called "Query's dark triangle". This region is one of the darker you can find over the French countryside. Indeed, the site was pretty dark : no lights on the horizon, a fair seeing despite a hight humidity level those nights. I had almost collected 60 frames for the luminance part, but 1 over 2 was corrupted due to dew issues

A special thanks to Marc R. for his support while setting up the mount and tube, and dealing with all the electrical issues we encountered. I swear never to buy again cheap chineese DC connectors

** Preprocessing détails **

- calibration simply using the BatchPrepocessing script (bias, darks, flats)

- manual cosmetic correction

- manual registration + images crop

- integration using winsorized sigma clipping for pixel rejection (high=2, low=4)

** Processing details **

>> Version A

I applied here my basic Pixisight workflow for LRGB images.

Luminance :

- no DBE

- star masks generation (coarse and fine)

- star size reduction (morphological selection, thr=0.05)

- HistogramTransform (using auto stretch from ScreenTransferFunction)

- Nebula mask with star excluded generation (ATW + PixelMath)

- Local Histogramm Equalization

- Noise reduction (ATW with k-denoise option)

- Histogramm check

RGB : DBE, BackgroundNeutralization, ColorCalibration, Histogramm transformation, saturation with luminance mask activated, ACDNR, remove green remanent (SCNR), Curves transformation (contrast)

LRGB Combination (lightness 0.55, saturation 0.45), ACDNR (one more time, amou,t 0.5 for lightness), final curves (saturation and contrast)

>> Version B/C/D

I added to A version the Ha data, using AIP HRGB script : 70% Ha in R channel, 50% R in Ha channel, transfer function for luminance = 0.40 lum, 0.60 satur, with chrominance noise reduction applied

Then, SCNR, star reduction (morpholigcal selection, seletion = 0.06, amount = 0.85) and final histogram transformation

>> Version E

A reprocess version of the LRGB data (no Ha applied)

>> Version F

A new HaRGB version (no L applied) with HaRVG from AIP (65% Ha, 35% R, satur 0.3, lum 0.5)