to make the lighting work if your using directional lighting and shadows, is that the you select your dome, then go to the attributes shape.

go to render stats, and switch off

cast shadows
and
receive shadows

Now you can start setting up your lighting.

Also make one ambient light and connect it only to the dome using the light linking tool.

And switch off any light linking from the directional lights to the dome.

So why is this, well now you have one light controlling the dome and the rest your scene.