3"x5" Glass Signal Mirror at 44 miles - digital zoom

These are flashes from a 3"x5" glass signal mirror, 44 miles away. This was a particularly clear day in Los Angeles - normally the air would not be clear enough for this. The mirror is a military issue MIL-M-18371E with retroreflective mesh aimer, as described at http://www.equipped.com/phony_signal_mirrors.htm . Sea Kayaker magazine had a nice 5 page review of signal mirrors, here: http://www.seakayakermag.com/2001/01Oct/mirror1.htm .

Category:

Science & Technology

Tags:

• signal mirror
• mil-m-18371E

[rafowell]

Red flashes stand out more, but filtering greatly reduces brightness, range and detectability. The US tried signal mirror color filters in the 1940s, then dropped the idea. At ranges under a mile, brightness is no problem, so the red might work. Google for "Safe signal mirror" to find retailers for the MPI Safe Signal Mirror: red mirror on one side, plain on the other. I think the plain Coghlan's Survival Signal Mirror (2"x3" glass) is better: the "fireball" aimer is key.

[spamerman]

Thats one hell of a shot to hit a camera with a mirror from 44 miles. Must have had a scope instead of a little peep hole, lol.

[rafowell]

@spamerman The beam spreads at roughly 50 feet per mile, so it's about 0.4 miles wide at 44 mile range. The retroreflective siming grid built into the mirror superimposes a phantom sun (an intensely bright, fuzzy "fireball") in the view through the grid in the direction the reflected beam is going. You just tilt the mirror to slew the center of the fireball across the target. The aimer is more like an AimPoint "red dot" gunsight than a scopes

[DonClardy65]

@bestSVMS eschew ambiguity: Morse SOS

[DonClardy65]

@bestSVMS eschew ambiguity:  Morse SOS

[Thenutzandbolts]

Sweet Dude thanks for setting it up

[ufoengines]

This make me want to build a Heliograph for some reason. If you show the flashes through a red filter, do you think that would help in making it easier to be seen?

[bestSVMS]

now whether soneone is willing to go that far to check it out is a differnt matter. cause it could be a random object.

[spamerman]

@rafowell lol I actualy knew all that I was kinda just bein a smart ass, I just didnt actualy know they were THIS afective.