This is just a plain old snapshot... no stacking or nothin'. not bad for the ol' iPhone, considering Iapetus is magnitude 11.4. Interestingly, Giovanni Cassini surmised waaaay back in 1705 that Iapetus had a dark and a light side and that it was tidally locked to Saturn, because he could see it easily on the western side of Saturn, but not the eastern side. Smart guy.
A single shot using the MagicShutter app, which was stretched and labelled in Paint Shop Pro. From Hammonds Plains, NS. Used an iPhone 4s, which was attached to my 8" SCT on a Nexstar mount.