I am trying to determine what is the exposure time that will yield the ideal ADU value for my ZWO ASI 1600MM. The camera is 12bit, therefore the maximum ADU is 4096 (2^12) and the flat frames should be 45% of that value (approximately 1800). I use Maxim DL which does not calculate the ADU. Therefore, I am using the mean value under the Statistics process menu on PixInsight.
Yesterday I took two flat frames with the Luminance filter:
A 0.03 secs frame which yields a mean value of 2236
A 0.025 secs frame which yields a mean value of 1868
When I inspect them visually I think the 0.025 secs frame is a bit too dark. I am more inclined to use the 0.03 secs exposure even though the median value is a bit over 50% of the 4096 max ADU. Here is the link to the dropbox with the two frames. https://www.dropbox.....2gyk9XqUa?dl=0
If I have to choose, should I go strictly by the numbers, or should I also take into account the brightness of the frame?