The orthogonality conundrum

[Jessun]

I did a run with the sig RC plus an Astro-Physics CCDT67 spaced at 101 mm to my Canon and given that my RC is ever so slightly out of collimation, this setup seemed to multiply this error by a mile, and looking at the stack it became obvious to me that the whole setup was tilted in the focuser making the worst affected stars pretty much take on a shape of a diamond as viewed side on.

It just seemed odd to me that often all we have to work with is a 2'' inch draw tube with a number of screws or perhaps a fancy compresson ring, and this is meant to align up to a few pounds worth of imaging kit with correctors protruding several inches into the tube! Pretty much balancing on a few millimeters of surface in contact!

I look at my SW screw on reducer and think that it's a great idea! Just not very common on other systems.

So how do you experienced imagers go about coupling your cam and reducer/corrector to the scope? Instinctively I feel like putting threads on the RC focuser to 'bolt on' the camera - tricky with 5 inches of extenders sticking out to hold the reducer!

I think there's so much room for improvement on this. I'd like to see a two inch extension ring that also has an external thread to attach to some corresponding unit fixed onto the draw tube... And adjusting screws on this unit too! To merely adjust the chip is not enough if the whole train is tilted...

Any thoughs?