Summer Travel Tips

[W. Larrison]

Unless one is already experienced with signal mirrors, you really need the eye targeting-hole to do it right

Actually, the central hole in the CD works pretty well as a targeting hole. The backside of most Cd's are silvered to get optimum performance, so they reflect the light pretty well. From what I've read it's only 1/4 to 1/3rd as reflective as a high quality mirror, but its reasonably sized as a reflector and just about everybody's car has one or several in them these days. There is an eye-targeting hole in the CD -- the central spindle hole. The instructions I've seen are to look through the hole, use both hands to hold the mirror, and sweep the reflected spot of light from the sun up and down across where you're trying to signal. It helps if you can line it up by sweeping the spot across the ground or through an outstretched V-of fingers so you know the spot is sweeping where you want, but that's true for just about every hand-held signalling mirror.

I've heard, but haven't seen, of someone who built a replica heliograph as used by the US military in the southwest, that used CD's as reflectors and plumbing parts for the shutter and structure. That was demonstrated at a local Boy Scout Scout-O-Rama and supposedly worked pretty well. But I have to confess, I never saw it personally.