Just as the sun sets the visible part of the spectrum rapidly diminishes and the effects of the UV spectrum become more noticable. as far as the Atsko product goes it is a very reasonably priced detergent that I believe was around before they started promoting it for hunters, I remember using it to was down clothes and sleeping bags. It came recommended from the manufacturers beacuse it rinses out leaving no residue on the down which would affect the lofting properties. Same reason it's good for hunting. ( I do use baking soda a lot too)