Jerry, that would be the case for mounting the camera looking through the scope. What I'm suggesting to Copernicus is mouning the camera on top of the telescope, not looking through the telescope at all. There, backfocus isn't an issue.
I think mounting it looking through the scope (using t-ring etc) should be the 2nd or 3rd step, once piggy-back astrophotography has been achieved, seeing as piggy-back is much easier to achieve... But that's just my opinnion.
Roger.