Encode place and date in star pattern Disclaimer: I'm an astronomy noob

You sometimes see in (B?) movies, that they infer dates from sky patterns. 
I was asking myself if you can encode a place and date in a mostly meaningful pattern? How would you do it? Would it be possible?

I was looking at 1 and maybe the relation between the visible planets? 
(Moon, Mars, Saturn)

Why: I want to make something special for my girlfriend (who likes "stars"), the date is special to us.
The position of stars in the sky has been used by navigators for a long time. For instance, astrolabs give you the time based on your position (or vice versa). And until GPS came along, airline pilots learned how to determine where they were using the stars. This comes with a few caveats however. 

Determining the date and place from just looking at the sky is ambiguous. Since the Earth rotates, the position of stars and planets at a given place and time is indistinguishable from their position a bit later (say a couple hours) and a bit further West (how many miles further West depends on your latitude). 
If you know what epoch you are in, you can determine the latitude by looking at the position of Polaris above the horizon. But to know longitude, you must also know the date and time. 

Because of precession and nutation, the star that is aligned with the axis of rotation of the Earth will change over long periods of time (roughly 25 000 years). So the position Polaris isn't even enough to know your latitude if you don't know what millennium you are in.