I'm a total newbie to long range shooting so I hope that this question (and future ones) don't make me sound too dumb. Last night I watched guys, on Youtube, shoot 800-1000 yards. I get the drop. How do they really know what the wind is doing? Is there a device for that or does this involve some guess work? Again, sorry for questions like this. I've never had to worry about such things in the duck blind.