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Narrow Band One Shot Colour with Dual Band Filters

Malcolm Park
in PixInsight
Hi,
I have watched the Eagle processing videos with OSC/dual band filters. 
My setup is different. 
My filters are Optolong L-Ultimate HA/O3 and Antlia ALP-Dual Band 5nm SII/Hb
So the usage of DBEXTRACT script is questionable. 
How would you proceed?
I think I'm good with the rest of the steps once I have my three working mono files. 
But the interesting thing to me is that the Hb might contribute to the blue in someway if I knew how to use it.

thanks,
Malcolm 


Comments

  • BlockHeadBlockHead
    Yep... and people wonder why I don't put everything in Fundamentals or introductory courses. Look how many combinations there are. Look how large NB as a topic is.

    Anyway- DBXtract will get the right result for the HA/OIII filter. So that is clear. 
    Then you can still use DBXTract for the other filter and get the right answer for SII... you do not need to run DBXtract with *both* fields populated right? So then you have Ha, SII and OIII.
    Now the Hb that DBXtract gives you that it thinks is OIII... I think it still be be correct... but of course it is just Hb and not OIII. I will need to look into this.

    The point is, you run DBXtract twice to output the images... not together which will average what it thinks is the OIII channels in each. 

    I will give this more thought... but I think that is the idea. 
    I probably need to connect with the developer.

    What to do with the Hb is a very different question. It is a line associated with H-alpha. It really just modifies the Ha for the most part by adding some blue to it (which you can just to manually). There are very few objects that have Hb that is not mapped with Ha in a one-to-one correspondence. 

    -the Blockhead
  • Malcolm Park
    thanks very much
  • BlockHeadBlockHead
    Worst case you can just extract the Red channel for the SII/Hb image.
    -the Blockhead
  • Malcolm Park
    edited August 2024
    thanks. 
    I am having trouble at the colour combine stage. 
    You always seem to be very close to target hue when it comes out of RGB Combine. 
    You got some green you didnt like, but the underlying colours were not far from where they ended up.
    My colour hues are not the same as yours and I dont like them at all. 
    Specifically, my reds seem to come out orange all the time.
    So I try to correct them and never get there. 
    Then I wonder why I think I'll ever get anything right.

  • BlockHeadBlockHead
    edited August 2024
    Malcolm,


    1. Different objects have different degrees of emission. I assume you are talking about using your own data. You did not indicate the object. The strategy can change.
    2. NB FastTrack is an introductory course. I mean come on..I can't possibly account for every variation in a single course? That isn't the point- the point is, if you understand the underlying concepts you can adapt and make images that do not "come out orange all the time."

    So let's start there because you specifically mention it:
    1. What color mapping are you using?
    2. If you are getting orange, what does this mean?
    3. Instead of orange, what do you WANT the mapping to be. Be precise! 

    -the Blockhead
  • Malcolm Park
    I'm not complaining about your course :) I love your material. period.

    The data was my own, and it was a different object. 
    It was a widefield of M8 and M20. I'm going to shelve that for now. 

    I just completed data collection on M16 in SHO with a very similar framing as your course data. It's mono data, but that shouldn't matter.
    I'll try processing it a few times, take notes, come back with specific questions, and not give in to my silly emotional responses. 

  • Malcolm Park
    edited August 2024
    I think I succeeded now I'm going to try to add SII :) 
    Capture.JPG
    1034 x 700 - 106K
  • BlockHeadBlockHead
    Yes... good. However, that image looks a little bright. Make certain it isn't too bright before you add the SII...and make certain the SII isn't too bright either. It will make it easier.

    -the Blockhead
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