In the case of Alpha Centauri, it is “only” four light years away. So we’re seeing it not as it was thousands of years ago, but as it was four years ago. There is no problem figuring out where it will be 20 years from now when our (robotic) spacecraft get there and charting our course accordingly.
They’re only halfway done with Obama, then.
Help is on the way, Alpha Centauri!!!