Night vision and smoke

[Dave]

Basic night vision question. I know that that NVG's extend your vision a bit into the infrared spectrum, allowing for things like IR flashlights and whatnot. Do your standard NVG's penetrate smoke? How about fog?

[workinwifdakids]

Hi, Dave! I don't think we've met. Pleased to make your acquaintance.

Basic night vision question. I know that that NVG's extend your vision a bit into the infrared spectrum, allowing for things like IR flashlights and whatnot. Do your standard NVG's penetrate smoke? How about fog?

I don't have an answer to your question, but the fine folks at http://www.tnvc.com are nationally recognized, and they're always quick to answer my questions. Best of luck!

EDIT:
When you find your answer, please post it for general knowledge.

[NVGdude]

No. NVGs generally see to about 900 nm. That is not long enough wavelength to penetrate either smoke or fog (or dust). They will see through very light fog better than the Mk. 1 eyeball, but it is dependent on the particle diameter (i.e. Rayleigh scattering)

To see through smoke you really need a FLIR system. I believe that SWIR will also work, but I don't have much experience with SWIR.

[Dave]

I managed to talk to a NVG guy at a conference this week and you are quite correct. Night vision doesn't work well on smoke, IR does. Rain kills IR while fog is bad for both of them.

He also indicated that IR tech had gotten to the point where you could mount them on helmets fairly reasonably. FYI.

[NVGdude]

Rain kills IR while fog is bad for both of them.

Essentially correct.

For FLIR systems, 4-5 micron sees through fog better than 2-3 micron systems, 2-3 micron sees through dust better than 4-5.
(this is why most US Navy systems are long wave IR and USAF are mid range IR)