Well lots of parameters in play off course, and my focussing it not on spot also.
But that counts for my pictures in my F/7 doubletalso and there it stays pretty much absent.
The 70 mm i bought for daylight bird observing actually so ..i went a bit the other way ...
Still a fine scope, on the moon i can get over 105x still have a tack sharp image....can get even much higher with some slight fuzzynes...
But not the best thing for AP i guess...