Back Focus, no Flattener or Correctors

[Figgis]

Hello All.

              Here's a thing.  I've had some good results imaging with my ZWO's.  I have a Coma Corrector on my Newt, and a Flattener for the Frac, but when I plug a Cam into my 127 Mak, I'm at a loss as to what Back Focus to set for best results.  Please can someone point me in the right direction, I'm getting a little tired screwing extensions together? 

[michael8554]

Just attach your camera to the Mak, there's omnly a back focus to consider if you're using a FF or FR.

Unless you're after some sort of "sweet spot" ?

Which might be when a combination of extensions give a Plate-Solved focal length of 1500mm.

Michael