Author Topic: M42 and M43 Additional Process?  (Read 54 times)

Offline dhb2206

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M42 and M43 Additional Process?
« on: 2019 February 11 08:09:12 »
As winter is upon us in the northern hemisphere Orion is a decent target. I've been building subs for a couple of months (i.e. about 4 nights as the weather hasn't been playing ball), all with a 300mm lens attached to a Canon DSLR riding on a Skywatcher Star Tracker. There are 282 1 minute light subs at F5.6 and ISO 1600 making up the integrated image, no darks, no flats and no bias. I'd guess about 25% of these are really good quality. Anyway, I've gotten to the end of a post processing run from a drizzled integration of a square 3500 x 3500 preview and would appreciate any tips on where I may have digressed or whether there is more that could be done to improve the image.

My run consisted of:

DBE - default sample generation at a tolerance of 2, samples shunted to avoid stars and deleted where there is obvious nebulosity, reigned back to 0.85 for normalised subtraction
MLT (Multiscale Linear Transform) for noise on layers 1 to 4 - 3 iterations at 0.5 application and thresholds: 4, 3, 2 and 1 masked by an inverse of a lightness abstract with applied STF stretch
Morphological Transformation - Erosion of 1 on a 7 structure applied to a star mask generated from the lightness mask
Histogram Transform on highlights to even out blown out R, G and B values (following a masked stretch and pink stars!)
Masked stretch on default values with a background preview active
MLT for noise stepped back on thresholds to 3, 2, 1, 0.5 masked by lightness extract auto clipped for shadows and highlights
ACDNR on defaults
Histogram Tranform to reset black point with minimal clipping
Curves Transform - tiny tweak of RGB for contrast and a reasonable saturation increase
HDRMT (HDR Mutiscal Transform) at 9 layers to lightness on a mask revealing just the core of M42

I'm pretty chuffed with the result though the jpeg doesn't do it justice (if I can get it to attach).....

I've stuck the files in a dropbox in case anyone fancies a play, but be aware, the files are large (575MB each)!

Base drizzle image is here:
Post processed image is here: