Having watched this again now, there is a definate 'sound effect' for it, so if you do decide to do something with it, it's probably easiest to just leave the little asteroid and it's shadow, rather than erase it, and just erase the 'glow'.
Also, while I don't really want to talk about 'Jedi' ideas on this thread, with the recent talk of replacing the beginning sequence with a 'different look' to 'A New Hope's' imagery, I'd just like to say that although I love the idea of the 'Executor' being involved instead, that I still hope the actual 'Jedi' overhead shot of the Stardestroyer is kept somewhere, as it is still a great visual, whether with 'shuttles' or not...