thats it Theo--when I rotated the camera to position NGC3576 in the right of the frame after taking a test shot I must have somehow got the camera a fraction off square to the optical path-this created massive coma ...must have been a fraction of a millimeter at best that I was off square but thats all it takes I suppose
well I suppose you learn from these things-I wont b in such a hurry to rotate the camera to reframe next time
Narayan