That's a Hooman signal, right there. My untrained game hacking would think of looking for some constants in the graphics drawing part. What exactly to look for, I have no idea.
From back when I tried to locate the game's chat system, I got a good look at how the game manages ticks, and as far as I can remember, all the day/night managing done in that area only involves moving the band of light.
Then again, maybe looking into that part that changes the band of light's location can give some clues.
I'm sorry if I can't be of much help...