You would easily be able to see on the dark side of a planet unless that planet was in a dark nebula with few visible stars. Much the same way anyone with reasonable vision can see quite well just using starlight. Even easier when there is moonlight.
Have you even been outside on a starry night (no moon) in an area with no street lights or light pollution from nearby populated areas? It's dark. Seriously dark. A moonlit night, certainly you will have plenty of ambient light depending on the phase.
If it lit up like it does due to a nearby moon, that would actually be cool...and realistic. Right now some of these planets look dark and once you get near it some diety turns up the dimmer switch slightly. Though like I said, I'm also finding planets that are pitch black. So that inconsistency seems like a bug. I'm hoping dark sides stay dark.