Military History/Unknown Military Equipment
I came into possession of a piece of military equipment a Lewyt Night Vision Scope Infrared US Navy WWII US/AM NAN R-1400 Spotting. There is nothing on the web pertaining to the operation, purpose or history of the device. My inquires to other historical entities have brought no elucidation about this device. I thought perhaps you could shed some light on this rare military item.
A little back ground. I studied remote sensing which in its first satellite form, relied heavily on IR sensors. Our eyes are not sensitive to that part of the spectrum but we can build instruments that are, and then do a color shift so we CAN see the IR part of the spectrun. IR was initially called black light, but then that was changed to refer only to Ultraviolet light, as seen in the 60's and 70's for illuminating fluorescent posters. I had some back then.
The Germans first developed IR for battlefield use both on tanks and on rifles, the Vampyr night scope being their man portable model.
We were developing IR night scopes as well. In the post WWII era we mounted large IR searchlights on our M-48 Patton tanks, above the main gun on the gun mantle.
IR is an active system meaning you have to illuminate the object you want to detect with IR radiation and object in this case the enemy does not know they are being lit up, but the good guys, that is us, can see them because we have scopes or viewers that allow us to see the IR illuminated enemy.
I cannot find any reference to the Navy using Large IR searchlights on ships, but I did find a reference to the submarine service using signal scopes for signalling clandestine operatives like commandos, or Marine raiders. IR beacons would be used to mark pickup points and presumably the sub would have a scope to be used to look for and "see" the IR beacon. What you might have is one of the scopes used to pick up the IR beacons.
here is a link to a beacon.
The only draw back to using IR is that if the enemy has an IR scope, your beacon or searchlight marks you as a target. That is why the services moved on to passive systems like thermal. You don't have to emitt any signature of your own to "see" their heat signature.
These are links to other viewing scopes.