That last lunar shot looks much better, Dennis! Looks like the USB cable isn't shielded
. I have a USB extension cable that I know is shielded - it has a steel braid around the outside
, but generally I'd be surprised if they are shielded.
Focus is often difficult... the worse the seeing is the harder it is to focus IMHO. I have tried the Hartmann mask, and the K3ccdtools focus aid, but in the end I think I've had best results by careful adjustment and taking a bit of time to watch the frames being captured... if I'm getting brief flashes of sharp frames through the seeing, then I know there's no point tryin to focus sharper.
Then I use registax to select the sharp ones... sometimes you don't end up with too many to stack, but even 30 is considered the lower end of statistical validity
.
Al.