In the interest of procrastination, here is an illustration of my point for your viewing pleasure. For those that don't know, red lights do not affect your night vision nearly as fast as an equally bright white light. Unfortunately I do not have a Bizer chart here with me.
The problem...when whatever you're looking at is exactly the same color as your red light...
...it disappears!
Very scary when you fly (at no more than 25mph) past 4 red buoys that "aren't on the map!"
