This looks like just what I need for my C11/Hyperstar 3 setup. Its a wonderful system and works well with my DSLR, but it's difficult to focus. I'm assuming that since the C11 with the Hyperstar is effectively f/2, I should, for the calculation, use a F.L. of 560mm (2x280) rather than the native F.L. of 2800mm. Could anyone comment? Thanks.
-------------------- Bill Richards
Celestron C11
William Optics ZS-105, ZS-80ST
Hyperstar 3
Canon/Hutech 350D
CCD Labs Qguide
Tak EM-200 Temma II