Friend of the Night

 is a perk in Fallout: New Vegas.

Effects
This perk causes a noticeable increase in brightness at nighttime. The effect is not a gradual one, and its presence can be recognized by a colored tint on the game world reflecting the dominant color of your surroundings (most often light blue when outdoors).

Keep in mind that once taken, the perk will always cause you to see the world differently at night.