From: mikko.syrjalahti@nospam.fi   
      
   sgpopticsguru@gmail.com writes:   
   >> This is removed in astronomy by taking 'bias images' in dark with   
   >> zero exposure time and substracting this from the image.   
      
   > Mikko, I do this. If you look at my description, I first measure FPN   
   > and take it out. Despite this I see a DC offset later which makes me wonder.   
      
   Ok, I was unfamiliar with the FPN term. Do you have a physical shutter   
   and what kind of sensor are you characterizing ?   
      
   If the strange DC level changes with light level and you do not   
   have a physical shutter, could this be optical/electrical leakage   
   on the sensor ?   
      
   --   
   Mikko OH2HVJ   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)