Narrowband Workflow Discussion

[Ryan Voykin]

I created a Powerpoint and YT video on my current workflow for Narrowband.  Wanted to open up a discussion and see what you guys are doing.  Depending on the target I may use different approaches but in general here is the order of operations for my NB images currently.  

 

Narrowband 1.3.pptx

[Andre B.]

This is really cool and helpful. I usually dont do a lot of Narrowband processing as I tend to get lost in the color workflow. This gives a great overview. Thanks for sharing!

[Alexander Curry]

This is a really great workflow! Thanks for sharing 🙂

[Jeff Horn]

Great video Ryan.  My NB workflow is pretty similar to your own.  I tend to work on each channel individually and only combine in nonlinear.  Only thing I do different is my stars.  I create a separate RGB-ish image using a pixelmath formula and follow the guide that Alberto Ibanez posted here...RGB Stars from Narroband Data – AIASTRO (wordpress.com)  I like the results from this and keeps me from doing separate RGB integration just for the stars.

I also do a light run of noise exterminator on each channel just to knock the fizz off before stretching.  

Thanks for sharing your workflow.  

 

[Ryan Voykin]

Jeff,

I also like to work on them individually, so you can get a little bit more customizable. 
 

Lately, I’ve been doing GHS with different Starr reduction amount depending on the filter, so 03 for example tends to have bigger stars than Ha so I’ll give it 25 instead of 20 or something similar.  
 

that way when I combine them, they match up well and you don’t get uneven spots

 

I’ve also used RGB style pixel math from thecoldestnights.com  It basically gives you more of a true color. Look closer to HOO.  I’m sure you’re using something similar and it also gives better stars like you mentioned.
 

The workflow in the video is pretty general I edit everything a little bit differently, depending on what I’m going for, but I just wanted to get a foundation for folks to follow, and then they can customize further from there. I left out some of the little tricks and things that I do especially in Photoshop, but I’ve put out videos on that stuff as well. 

 

[Ryan Voykin]

On 9/28/2023 at 7:51 AM, Alexander Curry said:

This is a really great workflow! Thanks for sharing 🙂

Absolutely hope it’s helpful.  It’s just a framework plenty of wiggle room to do your own thing but for total beginners who have no clue I wanted them to have something to work off of. I approach every target a little different depending on what I’m trying to do, but you can at least get from start to finish with this.

[Mark Mayer]

Great video.

SPCC is not designed to adjust/correct star colors for narrow band images. If you don't have RGB raw data, you can never recover true star colors from narrow band monochromatic images. It's kind of obvious when you think about it. With SHO narrow band you have deeper red, red & green filters. With HOO you have only red and green. Same for OSC dual narrow band filters: only HOO recorded. Adam block recently posted a video going into this in depth, but the bottom line is that SPCC is only useful for visually correct star colors if you have three filter, RGB data, or OSC data with a wide band filter.

My approach for narrow band SHO images is to extract stars, e.g. SXT, combine the three channels as RGB, use SCNR and correct magenta stars scripts, and that's my color star image for subsequent merging back into the starless nebula image.

For the starless narrow band nebula image I used to follow a similar approach to the one you describe, but the new narrow band normalization tool for PixInsight by Bill Blanshan and Mike Cranfield has completely changed my workflow. The major advantage is that it has real time preview and tools to adjust the three channels, so instead of iterative guesses with pixel math expressions, you can adjust your color balance in real time. Its an amazing advance that will forever change narrow band data processing.

[Ryan Voykin]

Updated workflow hope it helps

[Ryan Voykin]

On 10/18/2023 at 3:52 PM, Mark Mayer said:

Great video.

SPCC is not designed to adjust/correct star colors for narrow band images. If you don't have RGB raw data, you can never recover true star colors from narrow band monochromatic images. It's kind of obvious when you think about it. With SHO narrow band you have deeper red, red & green filters. With HOO you have only red and green. Same for OSC dual narrow band filters: only HOO recorded. Adam block recently posted a video going into this in depth, but the bottom line is that SPCC is only useful for visually correct star colors if you have three filter, RGB data, or OSC data with a wide band filter.

My approach for narrow band SHO images is to extract stars, e.g. SXT, combine the three channels as RGB, use SCNR and correct magenta stars scripts, and that's my color star image for subsequent merging back into the starless nebula image.

For the starless narrow band nebula image I used to follow a similar approach to the one you describe, but the new narrow band normalization tool for PixInsight by Bill Blanshan and Mike Cranfield has completely changed my workflow. The major advantage is that it has real time preview and tools to adjust the three channels, so instead of iterative guesses with pixel math expressions, you can adjust your color balance in real time. Its an amazing advance that will forever change narrow band data processing.

I've revised my NB workflow and put out a new video.  There was some confusion at first with SPCC and Narrowband.  If you look at some of the videos on Pixinsight's Youtube channel they were suggesting to use it for NB data as well.  But like you mentioned it's much more intended for more broadband data.  When I made the first video I posted it was still not definitive at that point as it is now.

As we know it's constantly changing and it was doing any "harm" to run spcc if the outcome was favorable I would just leave it, if not always each to undo it.  But now I rely more on linear fit, to equalize the channels, GHS, and occasionally NBN.  I do most of my color work in Photoshop but it's nice now that tools like Selective Color are now in pixinsight which I demonstrate at the end of my most recent video.