[ kaneki continues to look at the sky ]

The position of the stars in the sky depends on the latitude and longitude, and the position of the stars changes throughout the night due to the Earth's rotation. There are some constellations that are unique to specific regions, as well.

Which means you can figure out where you are. [ he does look back at the other before looking down, a bit embarrassed ]

... I don't know any constellations, though.