[Bart B.]

I would first ensure the scope reticule is in sharp focus as soon as you look through it at a clear blue sky. If not, adjust the scope eyepiece until that happens. Don't look through the scope more than one second else your eye will try to focus on a blurred image. Once instant views in the scope have the reticule sharp and clear, then check the scope focus range versus actual range.

With the scope fixed solid, moving your aiming eye around looking through it should have the reticule fixed in place on the target. If the target moves to the right of the reticule as your eye moves to the right, the scope's focused further than the target is. Move the scope's AO to a closer range. Use a further range if the target moves to the left of the reticule as your eye moves to the right.