[APML]: Evaluating sharpness of SCTs through photographs

[charles@cjf.noli.com]

Is there a way of evaluating the sharpness of SCTs through photographs?
I would assume that the more pinpoint the fainter stars, the better the
optics. The less soft the star images, the sharper the optics. There
must be some way to evaluate just how sharp. For instance, I have a
Celestron Ultima, and I have compared pictures taken with various Meade
SCTs (LX200, etc, as well as the plain C8 with no coatings). My images
seem at the high end of quality. I know that there are also focusing
issues involved. Any ideas?

C.S.