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I am looking for a good resource to learn pixel math (PM). I use Siril for processing and I've tried using PM with a little success. I just can't figure out what formulas to use to achieve various looks. this image was done with the following formula, saw it used on a tutorial from Deep Spae Astro. Shot with a L Extreme filter R Ha G .4*OIII + .6*Ha B OIII  The Elephant Trunk nebula sh2-131 For background, Siril OSC camera L-extreme and SII filters are being used |
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Here are a few useful expressions that I've collected from various sources, they all work with Siril: Narrowband Luminance = (Ha^2 + Oiii^2 + Sii^2)/(Ha + Oiii + Sii) RGB Luminance = (R^2 + G^2 + B^2)/(R + G + B) ==================================== SHO Foraxx Palette R = (Oiii^~Oiii)*Sii + ~(Oiii^~Oiii)*Ha G = ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Oiii B = Oiii ==================================== HOO Foraxx Palette R = Ha G = ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Oiii B = Oiii https://thecoldestnights.com/2020/06/pixinsight-dynamic-narrowband-combinations-with-pixelmath/ ==================================== Synthetic RGB from Narrowband R = 0.5*Ha + 0.5*Sii G = 0.5*Oiii + 0.094*Ha B = 0.295*Oiii + 0.1*Ha https://www.cloudynights.com/topic/661929-a-fresh-take-on-synthetic-rgb-from-narrowband/ =================================== Extract Ha & Oiii from Optolong L-eXtreme Ha = R Oiii = (2*G+B)/3 ================================== Ha Continuum Subtraction Ha - f * (R- med(R)) f = 0.13 approx |
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Keith Belzner: Looks good from here. |
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It looks like you're already getting the hang of it! Taman gave you a lot of useful combinations. After that it's a matter of small adjustments depending on your data and the look you want. I'm sure pixel math is capable of a lot more so don't be afraid to experiment.
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Here are a few useful expressions that I've collected from various sources, they all work with Siril: Thank you, I looked at the link under the HOO formula and it was helpful. I'm still looking for information that explains in a more basic way. Formulas are great to plug in but I want to understand the how's and why of it. again very helpful |
