Finding the position of an object 1800 years ago?

[solarblast]

I use the planetarium program The Sky quite a bit. It's capable of showing the sky from -4700 years ago to 10000 years into the future. What's the methodology behind this? One giant leap, or small leaps of say 100 years to get there, with some last jump to the final date?

 

[solarblast]

I believe the answer is that proper motions are used for each star seen in the virtual sky.

Google proper motion big dipper. One of the first hits shows what happens to the big dipper over something like 10K years.