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QE entry for OSC camera
#1
I have a ZWO ASI071 camera and am trying to figure out what to enter in they SkyTools 4 Imaging camera setup section for QE%.  The ZWO website shows a relative QE graph, with separate lines for the R, G, and B channels.  They say they "suppose" QE is 50%.

My take is that the debayer calculations essentially spreads the data from an active pixel for one channel to the surrounding inactive pixels.  For example, in a given row there might be a red, green, blue, green, etc. set of pixels.  The green pixels will receive some count of of green photons, while the red and blue will get very few green photons.  But the debayer algorithm will give the blue and red pixels a green-count that is an average of the surrounding green pixels.   The same happens with red and blue - the counts are spread out to the surrounding pixels.

So, while a given pixel might actually be receiving only photons of a given color, the end result in the image is as if it had been receiving photons of all 3 colors.  Based on this, I'm assuming that the correct value to enter into SkyTools would be to take a sum of the Relative QE graph values for the 3 channels at a particular wavelength, then divide by 2 due to the overall QE rating of 50%.

Is that correct or am I missing something?

-Dan
   
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#2
Hello,

What works best is to take the upper bound of the graph. So if the red line is the highest then adopt the red value, if green becomes higher, adopt that one, etc. As these are relative values, multiple each by the maximum absolute QE (jn this case 50).
Clear skies,
Greg

SkyTools Developer
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