Given upon completion of the game. It's simple, but here's a tip that made this and everything else simpler for me.
Go into your options ->Graphics options -> and turn (I think it's Gamma) up quite a bit. (Wait until it's actually dark though, or it will give you a headache.) This will make it so you never have to have a light source at all throughout any point of the game, and you can see all around you.