Okay, I have this great idea: I want to build some kind of giant astronomical calendar (think Stonehenge) such that it would have synched up with a celestial event that would have taken place 10,000 years ago, but wouldn’t work in modern times (due to stars shifting, whathave you), and I want to make it out of something like stainless steel or other material which wouldn’t have been available to people 10,000 years ago. The reason for this (heh, heh, heh) is to confuse the bejeezus out of future archeologists who find the thing. (Rat Archeologist #1: “This doesn’t make any sense! It only lines up with stars that were in the correct position millenia before humans had discovered stainless steel!”
Rat Archeologist #2: “Well, those humans were a crazy lot! That’s part of the reason they went extinct.”)
So, what all do I need to know to be able to do this? I know that to get a sundial oriented in the correct way, you need to have some idea of your lattitude and longetude, and I assume that there’s something similar I’d need to know to figure this out. Also, what kinds of astronomical events would work? I want something that would have stayed the same for at least a decade or so, but would have shifted to a different position by the beginning of the 20th Century at the latest.