SharpCap Forums

Hi,

After using the sensor analysis function to characterize the ZWO ASI290MM camera sensor,
the cursor value no longer agree with the Mean value printed on the
histogram (see attached figure). Before using the sensor analysis function these two
values were in agreement. The cursor value should be the correct value.

Cheers,
Jan

Hi Jan,

the cursor number is the 'True ADU', which for a 12 bit sensor is 16x less than the 'Scaled ADU' used in the mean on the right - this is not really clear enough though, so I will change to make it clearer. 16x67 is about 1060, so that is fine, but this should apply too for the standard deviations and doesn't seem to, so something odd going on there.

cheers,

Robin

Oops, my mistake, it's the 'Value' reading at the top that should match the mean and that's the one that's off. It was correct before I cut down the number of points being plotted on the graph to a maximum of 2000 or so to improve performance.

Also, the SD shown on the right is not supposed to be the same as the +/- shown next the the True ADU - again me muddling myself up... The one on the right is the histogram standard deviation (measure of the histogram peak width). The one on the True ADU line is the expected noise from the sensor at the selected ADU value from the sensor analysis noise model.

I will fix the 'Value' readout for the next build, and documentation will deal with the rest I think.

cheers,

Robin