Got rid of more flexure.
I have just fixed this last little bit of flexure by bolting a stabilizing bar between the two dovetails of my side by side.
It seems the camera and CFW just put too much torsion on the image train dovetail due to gravity at slowly changing orientations with changing lateral forces that cause flexure.
The RH200 meanwhile is sitting very stable and not moving while the dovetail it is bolted to is twisting at its rear due to a too heavy image train.
I measured this flexure before and after and it is almost gone.
Here is a bigger image where you can see the dial indicator and the rest in better detail.
http://d1355990.i49.quadrahosting.co...013_01/IMG.jpg
Test Images
LMC 3nm NII, 5x32 minutes exposure, PL16803 at -30C, all fits images are upsized before stacking by a factor of X1.5. 11MB
http://d1355990.i49.quadrahosting.co.../LMC_NII_M.jpg
NGC3576 and surrounds, 6x32 minutes. All other conditions same as LMC image. 10MB
http://d1355990.i49.quadrahosting.co.../NGC3576_M.jpg
Bolting down the tail of the dovetail worked!
Now I am off to fix the next smaller problem. Weather!
Bert