One of the clearest signs we live in a pinnacle of technology is that mathematicians and astronomers have been refining the equations that produce ephemerides for thousands of years, and the inverse problem (given star locations and time, predict ___location and pointing vector) to the point where an average human with average hardware can instantly estimate things that would have taken the world's most powerful observatories a great deal of effort to do.

https://en.wikipedia.org/wiki/Fundamental_ephemeris