Have spent the last 3 weeks enjoying star hopping with my new 12"GSO Dob and as yet I've not become entirely formalised in my approach. Be that as it may, I was admiring Jupiter on Friday night (27th-about 11 pm or thereabouts) and I'd put in the 15mm ep and I thought Jupiter looked a little distorted on the right hand side. Kept observing on and off for about half an hour and eventually I could discern one of the moons (no, I don"t know which one) coming out from behind Jupiter.
I guess it's no big deal and I know this is a shocking report, but I'd never seen it before and I thought it was spectacular!