FreeLists / az-observing / [AZ-Observing] Re: How deep can you see?

[brian.workman@xxxxxxxxxxxxx]

>Years ago, if you bought from a surplus store one of 
> Uncle Sam's
> angle neck milspec green flashlights, it came with a red 
> filter and a white
> and a clear diffuser to insert over the lamp. This same light 
> started to
> include a blue-green filter about year 1988. Supposedly this color was
> better for navigation and reading than the red. 

The blue-green filter you started seeing in the late '80s is used by the
military because it is compatible with the latest generation of night vision
goggles (Gen IV or NVIS). This particular color illuminates well enough to
see with at low intesities without wearing the goggles, but will not "bloom"
in (cause a blinding interference with) the night vision goggles. Thus a
mixed crew with some wearing goggles and some not will both be able to see
and function.

Rumor has it that one of the contributors in the tragedy of the aborted
commando attempt at rescuing the Iranian hostages in the early '80s occurred
when indicator lights in the cockpit were covered with duct tape to prevent
interference with the pilots goggles. A warning light illuminated and no one
saw it. The use of NVIS compatible lights in the cockpit is supposed to
prevent future occurrences of that problem.

I worked on cockpit controls and displays earlier in my career. 
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