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Pixinsight Workflow Suggestion

Processing SHO Narrowband Deep Sky
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Naiteek Vikamsey avatar
Naiteek Vikamsey avatar
I have been OSC imager since 8 years and now i am switching to Monochrome camera with full broadband and narrowband filters set

I have always looked to retain the original color balance of the object. Now with the use of SHO narrowband filters how am i suppose to retain orginal color tones? I m not interested in producing the hubble palette and any such false color images

What would be the correct way to map SHO to RGB channels?

S2 + Ha —— R Channel
O III —— G and B Channels 

Is it correct?
andrea tasselli avatar
andrea tasselli avatar
Not sure why you would want to do that. If you're aiming at HOO you don't need SII so you can spare that time to get more integration in the OIII and H-a channels, especially the OIII which is usually the weaker of the two (except for PNs, that is).  Otherwise, yes, that's correct in principle. Not sure what you mean by the other question.
Naiteek Vikamsey avatar
Naiteek Vikamsey avatar
Makes sense to get only Ha and OIII… But many objects do have a very strong SII signals, like the eagle nebula etc. So in that case what to do? And i have seen people mapping some Ha data into B channel as well along with R channel to make it appear pinkish, how about that?
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andrea tasselli avatar
andrea tasselli avatar
I'm not sure there are too many of them in the emission nebulae category, from what I've tested so far. So maybe M16 is the exception to the rule (since Sulfur is much less abundant than H, being only the 10th most abundant element in the Universe with O being 3rd). There are loads of different takes out there so feel free but then it isn't anywhere close to "natural" colors.If you want to retain a pinkish hue to the a nebula the right way is to add H-beta to the B channel (there other emission lines as well but they are much much weaker). In some instances H-alpha can act as a "proxy" for H-beta so I can see where they are coming from but I'd still go the "proper" way and use a H-Beta filter.
Ashraf AbuSara avatar
Ashraf AbuSara avatar
Yes you will need to blend the Sii data with the Ha data in the red channel. You might want to consider using the free Foraxx Palette Script. It utilizes and automates dynamic narrowband combinations with pixelmath. I believe it is closer to "natural" colors than straight SHO, especially for the star colors, and can be created from Ha / Oiii or Sii/Ha/Oiii data sets if you chose. Maybe give it a shot and see if you like the colors you are getting from it. 

In the end it is difficult to produce "natural colors" based on pixel math formulas because every target is different, and the only "true color image" is an RGB image but that would lose all the benefits of narrowband imaging.
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