Drakegoodman scanned this 1917-ish photo of Soviet planespotters in exotic headgear; according to a commenter, the binox are focused at infinity "so that when you found the source of the sound by turning your head, you could see the aircraft creating that sound."
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.