One thing that AnKor's shaders do that we don't always appreciate is that they provide different levels of lighting at night as well as in the daytime. If you fly when there is a full moon in the sky objects will be significantly brighter than on a moonless night.
AnKor will have to comment on how he is is setting the overall ambient light level at night, but the effect it has on the ground is controlled in Light.fx by #define GroundBrightness, and #define SunStrength effects both the Sun and the Moon intensity that it adds to the background of ambient light. I'm not sure where the ambient light effect on scenery objects is set.
As has been mentioned before, sometimes it's best controlled simply by temporarily turning down the brightness on your monitor.