[ZWO ASI 1600 MC Color] Capturing color FITS

Discussion in 'Image Capture' started by Bill Christie, Jun 16, 2016.

  1. Bill Christie

    Bill Christie Standard User

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    I can't find how Maxim DL can capture color FITS files for the ASI 1600 One Shot color camera.

    I am using Maxim DL to take DSO long exposures from ZWO ASI 1600 MC color camera. I have installed the ASCOM driver supplied on the camera's CD and configured it for unity gain.

    Whenever I take a picture the file saves as FITS (Monochrome header property.

    I can't figure out how to convert the data to color.

    Is there some trick/option that I'm missing ?
     
    Last edited: Jun 16, 2016
  2. Colin Haig

    Colin Haig Staff Member

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    Take a look under the menu Color... Convert Color. Generic RGB may do it, and I think you will need to play with the X, Y offsets.
    There's also Extract Bayer Plane that could be used to pull the individual R,G,B pixels out, then you could combine the images afterward.
     
  3. Bill Christie

    Bill Christie Standard User

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    Thanks. That may be ok for one image. How do I batch convert say 60 images ? Thanks again
     
  4. Doug

    Doug Staff Member

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    There is a Batch Process command.

    Better yet, if you are stacking the images, the Stack can automatically convert them as it loads them.
     
  5. Bill Christie

    Bill Christie Standard User

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    When I try both these ways in Maxim DL I get monochrome pictures.
     
  6. Doug

    Doug Staff Member

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  7. Bill Christie

    Bill Christie Standard User

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    Below is a closeup of the result - a picture taken with Maxim of a blue-green and white laundry object.
    The result below is AFTER applying the Convert Color command. Do I need somewhere in Maxim to specify the camera's Bayer planes ? e.g. GRBG ?
    upload_2016-6-18_6-18-17.png
     
  8. Doug

    Doug Staff Member

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  9. Bill Christie

    Bill Christie Standard User

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    How do I know what values to use for Offset X and Y? Is it trial and error? Seems I only get a visible change using either X=0;Y=1 OR X=1;Y=0. Either way the color is not natural.
     
  10. Colin Haig

    Colin Haig Staff Member

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    The Offsets are dependent on the chip in the camera and how its electronics work. It's fairly normal to have one of X=0 and Y = 1.
    Also, depending on the chip in the camera, you likely have 2 green pixels for 1 blue and red, so you may need to adjust the Scaling values down, e.g. set the Green to 50% for example.
    Plus, the sensitivity of each color is different - the microlens filters allow different amounts of light through, and the chip itself responds differently to different wavelengths).
    I had a quick look here:
    https://astronomy-imaging-camera.com/products/asi-cooled-cameras/asi1600mc-cool/
    and the Relative QE (Quantum Efficiency) chart shows peaks of 1.0 for green, 1.0 for red, and 0.8 for blue, so you need to do the reverse of this to bring up the levels. (Allowing for the green).
    So, you might try scaling of R 0.8, G 0.4, B 1.0 and see what that looks like.
    This is the ART that goes with the science of image processing.
    Also, your lighting makes a big difference. So, if its sunlight on a multicolor scene, you'll get the most natural color, and will want to calibrate from there.
     

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