Looks a bit like coma to me...but being out of focus can exacerbate this. How are you achieving fine focus? And are you focusing "up", by turning the focus knob anti-clockwise? The C9.25s I've seen seem to exhibit a little less field curvature than the bog-standard C8/C11 models, but visually it shows up as out of focus around the whole star, not streaking towards the edge. Of course it could be a combination of the two
Once I'd noticed the coma with my C8 visually, I couldn't "unsee" it and ended up replacing it with the Edge HD model
