NavList:

Frank,

"Of course the "real" way that we know it was 2020 and not 1921 or 1941 is because iPhones were hard to come by back then (unless you could capture a time traveller!). Is that information allowed?? Does that make it cheating? Maybe... It all depends on how you choose to play the game. What can we accept as "givens" from the verbal setup of the story before we dig into the astronomical and mathematical implications? It's fair to assume that a recent photo is a "recent photo" in this context unless you have some reason to question that assumption. It is at least a good place to begin. If we play the game in a more pure form and assume nothing about the photo, then as I say above, it is still solvable thanks to those faint stars and thanks to the fact that the Solar System never really repeats."

Setting aside the "givens" like iPhone and verbal setup of the story, i approached the puzzle purely from a astronomical point of view to make sure that the mathematical solution is repeatable for similar puzzles. I think i got this thanks to your explanation. It is those faint stars that made the day.

Cheers and happy holidays!!