U694 Amp Glow

Discussion in 'Aluma Series' started by mike m benjamin, Mar 24, 2020.

  1. mike m benjamin

    mike m benjamin Cyanogen Customer

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    I've had my camera for a few months now, I've noticed that about the longest exposure I can get away with is 300s with successful image calibration, i.e no leftover amp glow. Attached is a 600s ha exposure. This is my first Sony chip camera, is this due to the design of the Sony chip? I never had this issue with my Kaf chip cameras.
     

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  2. mike m benjamin

    mike m benjamin Cyanogen Customer

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    Here is a 300s fits to compare.
     

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  3. Colin Haig

    Colin Haig Staff Member

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    Mike, to tell if it is amp glow, dark frames will show it.
    Would you mind posting a couple of comparable dark frames?
     
  4. Doug

    Doug Staff Member

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    Yes please post 300s and 600s dark frames.

    I'll note that your 600s is Ha, whereas the 300s is Luminance. The L will have much higher background illumination.
     
  5. mike m benjamin

    mike m benjamin Cyanogen Customer

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    Sure Colin
     

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  6. Doug

    Doug Staff Member

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    Yes there is a small amount of amp glow there. However, when I subtract your dark from your light it is completely removed.
     
  7. Colin Haig

    Colin Haig Staff Member

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    I concur with Doug. The Sony chip layout is different from the Kodak-derived sensors. The Sony chips exhibit a small amount of amp glow in some of the corners and at the top.
     
  8. mike m benjamin

    mike m benjamin Cyanogen Customer

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    Including the 600s sub Doug? If so for some reason image calibration that I use in Pixinsight isn't doing the job.
     
  9. mike m benjamin

    mike m benjamin Cyanogen Customer

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    I'll try using Maxim Dl
     
  10. William B

    William B Cyanogen Customer

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    Hi Mike.

    With PI the calibration option "Optimise" should not be used if the dark frame has amp glow as the glow creates a false noise evaluation and the calibrated frame will be under-compensated.
    This is the case for most CMOS sensors and a few CCD's that show amp-glow.
     
  11. mike m benjamin

    mike m benjamin Cyanogen Customer

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    I figured this out trial and error this afternoon William. I was able to calibrate successfully using Maxim Dl first, so I knew it could be done. I do like the Kaf chip cameras as there is less work although the tradeoff is more noise.
     

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