My first time shooting this nebula. There's so much detail I wanted to go long. Fortunately, we had three clear nights straight.
For processing, I've fully embraced RC Astro's StarXTerminator and NoiseXTerminator plugins for PixInsight. They can be used on linear images, so I remove stars really early on. This lets me play with the nebulosity without worrying about blowing out or wrecking the stars. I can also easily stretch the nebula much more than I stretch the stars. Also, the plugins are optimized for my M1 Mac, so they run very efficiently.
I tried several combination to mix narrowband into RGB. I liked the one linked below the best for this target. It's unusual, but not too unnatural. And the :"dynamic" effects worked well to bring out the details. Thanks to
Cuiv for bringing it to my attention.
Processing1. WeightedBatchProcessing to calibrate, register, and integrate
2. Drizzle Integration
3. Dynamic Crop
4. Use EZ Decon on each image to generate PSF files, but don’t run EZ Decon (we’ll run that on the starless images)
5. StarXTerminator on each linear image, generating star masks
Starless1. PixelMath “K=0” to generate an all-black copy of any of the images
2. EZ Decon, on each
3. NoiseXTerminator on each
4. Arcsinhstretch on each, to taste
5. PixelMath to combine a
dynamic narrowband mix:
- R = (Oiii^~Oiii)*Sii + ~(Oiii^~Oiii)*Ha
- G = ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Oiii
- B = Oiii
6. use LRGB Combination to re-apply H to RGB (checking only L component)
7. CurvesTransformation
Stars1. LinearFit Ha and SII to OIII
2. ChannelCombination
3. HistogramTransformation
4. Invert, SCNR on green, then Invert again, to get rid of a purple cast
Combination1. PixelMath: 1-((1-SHO)*(1-stars))
2. Some touchup in Photoshop (including allowing some extra big stars to pop through)
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