First of all, sorry to anyone else in Southeastern Europe, the 6 weeks of almost uninterrupted cloud were probably brought on by me going shopping

The curse appears to have been lifted this week, though, and my new lens and my new mount had their first light together, on an object that I knew I could make look good even with a short total exposure.

1 stack of 50 45s images, Canon 800D at ISO 800, Canon 400mm f5.6 lens wide open, iOptron Skyguider Pro tracker. 100 darks, 350 biases. Processed in PixInsight as below

***** Integration

lightvortexastronomy tutorial (https://www.lightvortexastronomy.com/tutorial-pre-processing-calibrating-and-stacking-images-in-pixinsight.html)

* CC defect list + master dark (sigma = 8)

(15*(1-(FWHM-FWHMMin)/(FWHMMax-FWHMMin)) + 35*(1-(Eccentricity-EccentricityMin)/(EccentricityMax-EccentricityMin)) + 20*(SNRWeight-SNRWeightMin)/(SNRWeightMax-SNRWeightMin))+30(15*(1-(FWHM-FWHMMin)/(FWHMMax-FWHMMin)) + 35*(1-(Eccentricity-EccentricityMin)/(EccentricityMax-EccentricityMin)) + 20*(SNRWeight-SNRWeightMin)/(SNRWeightMax-SNRWeightMin))+30

* img 3067 ref

* generalized ESD integration, low/high range cutoffs of 0.02

* drizzle integration, gaussian kernel, enable CFA drizzle

*****Linear processing

*** Initial

* Crop

* DBE tolerance 2

***Color calibration

* BN from preview, upper limit 0.0013

* PCC on M42, FL 400 pixel size 2um, BN upper limit 0.0013 from background

* BN some more on starless preview, upper limit 0.01

* PCC again, starless preview BN with upper limit 0.01

*** Deconvolution

** Background mask

* GAME to create ellipsoids on Orion and Running Man, gradient mask

* EZDecon background mask, histo stretch highs=0.5

* max(ez_bg, gradient_mask) = background_mask. Clonestamp edges, blur 6 layers of a trous

** Star mask: EzDecon star mask, hand-added ovals on righter nebula stars, dilate boost convolve boost x 2

** PSF: EzDecon

** Run EzDecon with above masks, 50 iterations, 8 pixelmath iterations

*** Clone stamp out dust spot

*** EZDenoise (as per Jon Rista's method at https://jonrista.com/the-astrophotographers-guide/pixinsights/effective-noise-reduction-part-2/ , using the automated scripts at https://darkarchon.internet-box.ch:8443/)

* TGV - default settings except edge protection 5E-5

* MMT - default settings

***** Nonlinear processing

**** Initial stretch

*** Extract luminance, apply luminance stretch

* EZsoftstretch

* EZHDR 5 layers 40 mix, meld with (1 * m42_L + 2 * hdr) / 3

* curves RGB darken bottom quite a bit, slight s-shaped curve

* ultimately ended up not using this for stuff other than star mask creation for star core fixes

*** Chrominance stretch:

* arcsinh stretch factor 227 black point 0.001

*** Color fixes

** Basic clean:

* color denoise: ACDNR on chrominance, with lightness mask, stdev 4 6 iterations

* 1 more PCC with background neutralization on upper limit 0.1 and background

* curves, pull green down slightly

* 1 more background neutralization

** star core fixes

* star mask for core fixing: from HDR luminance extract range mask 0.91-1, fuzzy 0.1, then star mask with starnet and histo stretch it high 0.5 mid 0.25. max(star_mask, range_mask), fix some nebula center messes with clone stamp, blur 3 a trous layers

* split into RGB, iif(m42_R > L & m42_B > L, (m42_R + m42_B / 2), m42_G), recombine into cores

* m42 = cores * star_mask + m42 * (1 - star_mask)

** contrast (since we won't be doing a LRGB mix after all because it looks like crap)

* curves, s-shaped contrast RGB curve, almost flat on dark side and not super large on big side

* curves again, slight notch in darkest 1/6 of L and flat rise otherwise (sqrt sign, basically), slight s-shaped boost in saturation

** finishers for this stage:

* HDR fix

* SNCR green

***MLT stretch

http://www.stelleelettroniche.it/en/2014/09/astrophoto/m42-ngc1975-multilayer-processing-first-part/

**Initial (fine details)

* created a new multiscale linear transform, kept 5 layers

* diffed from original image to create a "blurred" version of original image

* extracted luminance from original, histo stretch shadows 0.1 mids 0.3 highs 0.7 used as mask on blurred version

* used curves to create s shape in RGB (asymmetrical, like a camera curve) and pump up saturation a lot

* pixelmath sum the 3, rescaled, back to original image

**Second (nebula)

* created a new multiscale linear transform, kept 7 layers, and diff from original

* extract luminance from diff, histo stretch shadows 0.02 mids 0.25. Blur 4 layers of a trous transform. Histo stretch again shadows 0.03 mids 0.35. Use as mask on blurred version

* s-shaped luminance curve, boosting 2/3 darkest and dialing down 1/3 lightest, big sat boost

*** Finishers

* LHE kernel 512 contrast limit 1.5 amount 0.5

* with star mask on, boost saturation

* EZDenoise, TGV on luminance, edge protection -3, MMT on luminance

* Dark structure enhance

* Curves, slight boost in G and R

* MMT sharpen, 6 layers biases 0.1 0.1 0.05 0.05 0.25 0.12