The edge HD optics have an issue.
Attaching a crayford focuser will might not work as the field flattener on the edge HD has about 1/4 inch of give in the CCD placement. So it's kind of interesting, I'd like to lock down the primary mirror near focus point, and then use a crayford to get perfect focus but I don't know if that's possible with such a small window of motion. But then again, if I get a focuser on the primary mirror knob then I won't be locking the primary mirror in place so it doesn't move as the mount travels past the meridian. Thus, I'm conflicted!!