Is this collimation, sensor to FR spacing or by bad imaging

[Ewan]

Hi (again sorry), from early this morning, got my CG-5GT mount nicely polar aligned, best it's ever been, i managed some 90 sec subs of M81 & i did this M44 @ 60 secs Iso 800, the picture is way better than i had hoped to be honest, why are the outer stars trailing at top right & what looks like coma on the left but looks pretty good in the middle ?

I was thing FR spacing to sensor but, i may be living in hope here, i thought as i had a Celestron FR & Celestron SCT adapter to the T Ring that the spacing would be correct, do i measure from the face of the FR glass to the Focal Plane mark on the Canon ? this is from the Celestron website

'For the Celestron reducer with a focal length of 231mm working at f/6.3, the spacing is 105mm. For Celestron accessories simply screw the reducer onto your scope and view at f/6.3. For aftermarket uses the compression ranges from about 0.7 at 50mm spacing to about 0.5 at 225mm spacing.'

As the FR & SCT adapter are threaded i cannot change the spacing which leads me to believe the spacing is correct.

I do not know if collimation would cause this so if anyone has any idea's i would love to hear them.

Thanks for looking / reading.