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WBPP for NSG

John Kmetz
in PixInsight
In the recent NSG Part 1 video, we see data files being added using the WBPP directory button, uploading many folders quickly. While this seems like a great time saver, are we now saying that WBPP is so good now we don't need to Blink through the light files and assume the rejection algorithms will reject fits files with clouds, planes and other offending artifacts?

Thanks,

John


Comments

  • BlockHeadBlockHead
    Hi John,

    A couple of things. The directory button is, as you know, loading the files based on what is in the Fits Headers. 
    I just wanted to say that I do not see a strong correlation between this and blinking through light frames. 

    Furthermore, I would say that you should check *all* frames if there is any question as to their content and quality. I have seen that many people think the calibration should just work... but it is of course possible to have calibration data that just doesn't work.

    But you don't do that right? Why?? I don't check all of my dark frames *every time* because I know with good confidence what they look like, and that the camera is going to give me what I need. I also know what to look out for in the rare chance something is not right.

    So now I can answer the question. WBPP now has weighting schemes and minimum weight tolerances. In many cases this can be sufficient to weed out the absolute useless data by outright rejecting it - or giving it very low weight. But I can do this and rely on this new capability because I know what the quality of my light frames - just like I do not examine every dark frame- that I am adding to WBPP with good confidence. I know I didn't have any guiding issues... no reason to think so, I have my equipment running well, I know there weren't any completely cloudy nights...etc etc. 

    Does this mean I am saying that "WBPP" is so good that we don't need to Blink.." NO! It means I AM SO GOOD that I do not need to blink. I already know with good confidence what kind of light frames are going in so that I can rely on the weighting schemes. 

    So my answer to you is .. .if YOU ARE SO GOOD that you know your data and you know what to look for- yeah, you can sometimes not even bother to blink. But. you never absolve yourself from the chore- it is you, not WBPP- that needs to know that all of the stuff that can be handled through rejection and weighting. 

    A case in point- with my widefield work- although frames with some clouds get the proper weighting- one issue is that clouds can cause bright stars to have large halos. These halos will still show up in the final image dimly since they will not be rejected entirely. So in this situation, I might blink through the data and only seek out these frames. Takes me two minutes of my time. 

    In some cases there is definitely a time consideration. You might weight how long it takes you to blink through the frames to how long it takes WBPP to do its thing. That ratio of time might be significant if there are many short exposures with hundreds of frames. The time savings of discovering the rare issue by blinking might still make sense compared to discovering the issue after many hours of useless processing.

    -the Blockhead
  • John Kmetz
    Thanks Adam. You answered my question thoroughly. But my Bortle 7 skies often yield lots of junk data that needs to be trashed. So I "wish" didn't have to Blink through it all, especially since my imaging extends a few hours at a time over many nights, and is enclosed in many separate folders. So it takes time to locate each object though many data sets, check it with Blink, discard the lesser ones, and then load the good ones into WBPP. So perhaps such automated discrimination might come into reality with scripts or AI or something else in the near future :).

    CS,

    John
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