Hi Keith,

I was just playing around with some of your data as there was something that was bothering me when I first looked that I didn't get to the bottom of, which is why you were getting zero stars with the Default Convolution parameter (which I've never seen before). The reason is that StellarSolver is getting a deblending error. I don't know exactly why at the moment, I suspect it's a bug and if I had to guess, it's probably related to the size of the sensor.

Anyway, you don't really need deblending for Focusing so if you disable it (set Thresh = 1) then I think it will work well. This is an example of your focus data (not using SEP) on my test system - solves quite well using SEP. I've taken some of the other restrictions like number stars off as I have a fast enough machine to process this, as well as the 10 pixels max star size and ellipse constraint...