The unseen passage of time happens a lot in ESB. e.g. In Echo base, we go straight from seeing Threepio in the control room to seeing him in the hangar.

This does not indicate that Threepio has teleportation abilities. It indicates we've jumped forward a bit. There's nothing unusual about this and it happens a lot in film in general.

Likewise, there is no problem at all with the size of the asteroid in that first shot. Seeing it close up in the next is the indicator to say we've just skipped forward.

The only thing I might suggest for the asteroid (as mentioned a while ago in this thread) is to slow it down or stabilise it entirely to give it a bit more mass.