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Workflow to combine data from two different telescopes

Bruce Donzanti
in PixInsight
In a few weeks, I will be attempting to combine data from two different focal length scopes to create a single image.  I know many folks do this but this will be my first try at it.  With that said, is there a workflow that has been used which can help me get started?  I believe DynamicAlign is involved but that is all I am aware of at this point.  

Thx
Bruce

Comments

  • BlockHeadBlockHead
    Aligning different images with DynamicAlignment is pretty trivial. I do demonstrate how to do this with a few videos (M1 Crab Nebula was one). 

    The real issue is alignment is going to interpolate pixel values. Both the difference in image scale and the interpolation affect the weights given to the images. What I have not seen done correctly is assigning the correct weights to each of the resulting images to be combined. 

    If you do not care how much weight each image is given... then this isn't an issue. But for me, this is the important part. I only want the data with the best signal to be given the most relevance. If not taken care of, it is possible to give poorer quality data the best weight and it will contribute more.

    I am assuming you are integrating the data together. If you are just going to make a composite, that is a different story. Llinear Fit (or NSG) and Substitute Script will do the job.
    -the Blockhead
  • Bruce Donzanti
    Correct on two points:  

    1- I am integrating the data together from two different image scales

    2- I only want the data with the best signal to be given the most relevance

    But I am still unclear how to proceed 
  • BlockHeadBlockHead
    It is somewhat non-trivial and I have not seen a tutorial that touches on this subject or explains it at all.
    I discussed this with John Murphy some time ago as it became important for one of my own projects- NGC 1232. I combined data from *three* different telescopes. (different focal lengths, different sensors).

    I believe there is a scaling factor that corrects for the image plate scale and another that compensates for the difference in gain between sensors. Then when PI integrates everything, the weights are correct.

    -the Blockhead
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