Processing result of the preliminary LRGB data from the Big Amateur Telescope (B.A.T.)

LRGB data contributed to this image by the following B.A.T. Discord members ...

Paranoider Ninja (Bortle class 5 sky):
TS Optics N 254 Carbon Photon @ f/4 + ZWO ASI 071 MC Pro  
L: 6.25 h
RGB: 6.17 h / channel

@Pam Whitfield (Bortle class 5 sky):
Explore Scientific ED102 CF APO + QHY9
L: 5.3 h

@reglogge (Bortle class 7 sky):
TS Optics Photoline 115 mm @ f/5.5 Triplet APO + ZWO ASI 183 MM Pro
L: 20 h

The BAT Man (Bortle class 5 sky):
William Optics FLT 132 Triplet APO @ f/5.6 + Atik 460ex mono CCD
L: 3.25 h

@MrCrazyPhysicist  (myself, Bortle class 4 sky):
C 14 Edge HD + Hyperstar V2 + ZWO ASI 1600 MM Pro
L: 6.5 h

The Big Amateur Telescope (B.A.T.), initiated by Astrobiscuit, is a collaboration of amateur astronomers, who share their data in order to create deep, high-resolution images of Deep Sky objects and time-lapse animations of variable nebulae.

If you want to contribute data for this or other targets to the B.A.T. or help processing data, follow this link to the B.A.T. Discord server:

https://discord.gg/WK8qmrqcpq

Remaining issues: Star colors/fringes are quite crappy due to the different data sources of RGB and L data. Will try to correct this in the final image ...

Large parts of the new workflow are based on the PixInsight Fundamental Videos for NGC 3486 (2021 version) by Adam Block

Post-Processing:

PixInsight

LRGB channel
star alignment of B.A.T. data, NSG script, dynamic crop, dynamic background extraction

RGB processing part 1
linear fit of G & B channels wrt R channel, RGB channel combination, PCC, SCNR

L processing (histogram stretch)
L_masked = masked stretch, L_manual = manual histogram stretch

arithmetic average of both stretches with PixelMath:
L_enhanced = .5 * (L_masked + L_manual)

HDRMT: Number of layers = 7, Scaling function: Gaussian (5), Deringing

RGB processing part 2
masked stretch, color saturation enhancement using curves transformations

LRGB processing
LRGB combination with chrominance noise reduction, color saturation enhancement using curves transformations, remove green tint with histogram transformations

LRGB_MMT = MMT with Bias = 0.1 on layer 4

create new LRGB_new = max(LRGB_MMT,LRGB)*.75 + min(LRGB_MMT,LRGB)*.25

create luminance mask, apply luminance mask, increase color saturation of galaxy, invert luminance mask, desaturate and darken the background with curves transformations, invert luminance mask, increase color saturation of galaxy again, remove luminance mask

Blend script: create new image Soft_light = Softlight of LRGB_new with itself, apply luminance mask to LRGB_new, create new image LRGB_softlight = combination of Soft_light with luminance masked LRGB_new image with PixelMath

Sharpening of L
enhanced luminance sharpening using this video by VisibleDark based on this tutorial on chaoticnebula.com

Starless processing
Star removal with StarNet2

Topaz Denoise AI:
Remove noise from starless image:
Low Light Mode On
Sharpen: 0
Remove Noise: 1

Finally, add stars to starless image using Pixelmath, final contrast/color saturation enhancements with curves transformations and color corrections with histogram transformations.