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Why does my image look so different

Jerald Kamienski
in PixInsight
Hello Adam

I'm relatively new to narrowband imaging. I recently imaged M57 and processed the image using the workflow techniques you published earlier this month. When I finished processing the image I went to Astrobin to see how my image compared to what others had done. I was surprised to find that my image stood out as an exception. Leaving me wondering why? I reran WBPP and performed the basic image processing steps and came up with the same result. Going back to Astrobin and digging a bit deeper I discovered, in part, why my image was different. My image clearly shows galaxy IC 1296. only a handful of M57 images on Astrobin showed this galaxy. Those that did, looked somewhat similar to mine. What they had in common was relatively long integration times. 

The second part of my question relates to the actual processing steps/techniques you outline in your workflow. All the images I found on Astrobin that looked similar to mine were actually quite different in detail and color. Obviously no two people will process an image the same way. In my case I'm just getting started and want to create a basic workflow that I can build upon as I gain more experience. Can you provide me a bit of guidance on how I can, shall we say, build upon your workflow.

I live in SoCal in a Bortle 6 area. I also have to contend with a street light that is located directly adjacent to my back yard. That said, even with a full moon I can successfully image in narrowband. Our weather is relatively mild year round thus supporting long integration times. Of course I'm repeatedly asking myself how much integration time is really enough.

M57 
Image Integration times
H 3nm -106 frames 240s (7hr 4min)
O 3nm -117 frames 240s (7hr 48min)
S 3nm -99  frames 240s (6hr 36min)

Equipment
TEC AP140 Telescope
ASI 533mm Camera
AM5 Mount

Thanks
Jerry  
M57.jpg
1891 x 1770 - 2M

Comments

  • BlockHeadBlockHead
    edited August 2024
    Hi Jerry,

    I have many answers to your question... but also many questions because I do not know what you did.
    I would like to say that my content on NB FastTrack is not to show you step-by-step that works for all objects. This is unreasonable for narrowband imaging. It really does matter a lot more than broadband what is going on with the object.

    Instead I am concentrating on offering an approach. I am trying to teach how to decide a mapping that might be interesting or easy to do (given the object) and how to achieve the results. You show an image of the ring nebula that is blue (and clipped). Then you ask why does your image looks different than others after following my workflow. The answer is because... it isn't the workflow that is important... it is the approach.

    You begin with deciding how to map the colors based on what you see in the data. I am guessing you did not want the ring nebula to end up blue. So which approach did you use? What color mapping did you intend? Did you attempt to blend everything with SHO or HSO? Did you adjust the sliders in NBN? Did you instead make an HOO image first and then add the SII? 

    The latter is very likely the easier route..
    Upon looking at NB images of the ring on Astrobin...I am pretty uninspired. I think there is room for better.

    So in order to make my point I have started to reprocess the Helix Nebula. You can start watching it now. I have three sections already.
    and

    -the Blockhead

  • Jerald Kamienski
    Hi Adam,

    Just prior to reading your comment. I looked at your most recent videos and saw the 4 fasttrack Helix videos and remarked to myself how timely they were. I didn't realize they were inspired by my forum post.

    Thank you very much for takin the time to produce them. 

    Jerry
  • BlockHeadBlockHead
    edited August 2024
    I did plan on doing it..but your post indeed motivate me to do it NOW. lol

    I think the approach I show would be very similar.
    1. Produce the HOO version of the image. You might need to do the slow stretch/HDRMT.
    2. Create a colorized SII..that is not to bright. Use NBColorMapper.
    3. Incorporate with ImageBlend

    This should allow you to maintain color. Specifically for the ring- my approach like the helix would have the red and green/blue in the large halo. I have not seen the SII for the Ring..but I suspect it is mostly in the brighter area. So this would bring yellow/orange in there.

    -the Blockhead
  • Jerald Kamienski
     Hello Adam,

    I want to thank you again for producing the Fastrack Helix videos. I've started to reprocess my image using the principles and techniques you present in these videos. The biggest issue I'm faced with is that my very limited experience with NB image processing does not give me the insight you have when it comes to choosing exactly what approach to use. It will come with time. But for now I have to rely on your expertise to keep me on the straight and narrow.

    My next requests.

    1. Would you please provide me the names of a few other bright NB targets that would be good candidates for processing using the principals/techniques outlined in the Helix videos.

    2. Now to the question of processing diffuse nebula. Do you have a recommendation as to what videos, that you have already produced, I should use for guidance to begin processing these types of nebula, along with a few recommendations of nebula that are good candidates for beginners like myself to build the foundation of a workflow to process this class of nebula.

    Thanks again
    Jerry 

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