Great shots John
Guys...there's a problem with the dust mote theory. Watch the second, slower animation. If they were dust motes, no matter what you tried to do, they wouldn't move as you took a series of shots, they would stay roughly in the same place as you ran the animation.
Watch the darkest of the "patches" in the animation. You can see aspect changes in the shape of the spot which are indicative of something rotating into and out of view. It would've been made easier if John had've taken more subs to smooth the rotation of the spot out more, but it is pretty clear that whatever was imaged there is not a dust mote but is rotating fairly synchronously with the body of the planet. Since the spokes and other phenomena of the rings has possibly to do with the influence of the magnetic field of the planet on the particles, as well as the presence of shepherding objects within the rings themselves, it seems most likely that the phenomena we see here is local to the rings, and due to those influences.