I'm amazed at people who are stupefied by software's ability to know where the stars are today, without any external sensors. They have known trajectories, it's trivial to calculate the position.
Well, I don't know if I would say it's trivial. Geocentric is fairly easy, topocentric (which is what we want), not so much. Especially when you have to start factoring in local time. And then people start wanting to change the time to a few thousand years in the past and now you have to factor in nutation and drift and ....
