›

LBN688 - A processing challenge for me

Ronald Clanton
in PixInsight
Adam,

I imaged the above target last night and found it very challenging to process.  It is rarely imaged, but it reminds me a bit of NGC1333... which you walked us through last month.  I used some of the techniques described there... but feel that I'm still missing something.

I think that the data is fairly good.  I used my 8" EdgeHD with the HyperStar attached (F/1.9) to a ASI533MC Pro in Bortle 5 skies with average seeing/transparency.  I only used a UV/IR Cut filter.

I'm a relatively new student of yours, but feel I'm am really learning a lot.  Very thankful!  It would be great if you, or anyone else, would show me what I'm missing!

Here are the links to the integrated XISF file and my final JPEG.



Thanks!

Ron Clanton
LBN688.jpg
2889 x 2640 - 7M

Comments

  • BlockHeadBlockHead
    This looks pretty good to me. It is kind of amazing. New students think they can walk in and take images of LBNxxx. Just 15 years ago this would be absolutely unheard of! :)
    Since this object is so faint the issues are caused by sky being the same brightness as the object. 

    So from what I see:

    1. This is an object that has little to no color. Perhaps some of the brightest bits have some... but this is more like IFN than like the dust found in the field of NGC 1333. So the goal is to achieve a neutral background. 
    2. The gradients in the image are still too large. You may have to apply multiple iterations of DBE with higher (or the highest) tolerance. You certainly can get a flatter field.
    3. I do wonder though- if you did not use the interactive LN... you definitely should have. These gradients are too complex. If these gradients are like this in any one subframe- you will need to work on minimizing them by generating better flats. The fainter the target...the better the flats have to be.
    4. I am surprised by the noise as it currently appears in the image NXT should really be able to help here. You did not state your exposure time... but this kind of object will require no less than 10-15 hours... This really isn't the kind of object by Bortle 5.. this is a dark sky object. No way to do an end run around physics.

    -the Blockhead
  • Ronald Clanton
    Thanks Adam!

    Yes, I undoubtedly was imaging beyond my learning!  I just wanted to stretch a bit to see what I can do.

    I admit that I struggled the most with DBE... the complexity made it difficult for me to know when the gradients were all removed.  Maybe my eyes just aren't that good... I'm 67 years old.  Are there any techniques to help discern the gradients better?  I'm going to watch those DBE videos again.

    I took fresh flats before imaging, but I will try interactive LN.

    I used NXT, but I'm usually a little on the conservative side in its use.  Will give it another go.

    With the HyperStar (F/1.9), I took 120 exposures at 120 seconds.

    Thanks for the observations.  This is definitely a journey, but the challenge is fun.  Your tutorials have certainly accelerated the process!

    Ron
  • BlockHeadBlockHead
    Hi Ronald,

    Concerning the gradients, you image has blue on one side and green on the other. 
    The result of DBE should be pretty flat in terms of the large scale color gradiens.
    There also appears to be a very low electronic noise. (You might want to make certain you have a good cable and that cable is not near anything else to invoke crosstalk.) 
    As I mentioned (correctly... yay!)- I did not feel you had enough exposure time even if you were under a dark sky. You have to beat down these other issues in order to make the nebula stand out more and be easier to work with. Really, only a darker sky would be the key for this object.

    -the Blockhead
  • Ronald Clanton
    Thanks Adam!

    I'll take more exposures and keep working on my techniques!

    And yes... you are always right! LOL!

    Ron
  • Ronald Clanton
    Adam,

    I'm attempting to solve the "low electronic noise" issue.  I've replaced and rerouted the cables... hope that fixed it.

    So... what's the easiest way to reveal this noise?  It seemed to only show itself on the very faint images... and even then it was difficult.

    Thanks,

    Ron
  • BlockHeadBlockHead
    Yeah... replacing cables and moving them. If not cables.. you start to think about the sensor. 

    you should check if it shows up in your master biases...  (or darks)

    -the Blockhead
Sign In or Register to comment.