Military History/NV Scope
This is a follow on question from 2013. I have a friend with a Lewyt Corp. NV scope/mono. It's serial number is 5385, Type "US/AM" and was under Navy Contract # NOBS 13750...if that helps. He asked me to see if I could find any info about it. It was left to him by his father so I'm thinking it was Korean or WW II , as you had spoken of in a previous response to another reader.
Thank you in advance for any insight you may have.
Lewyt sold out to another company in the late 1950s so defiantly Korean War vintage. I would presume this is a R1400. The 1400 had another name the Metascope. Metascopes were a low gain
infrared scope. Typically you needed an infrared light to illuminate your target. The r1499 was used on ships for signaling other ships without being seen and with Seals and marines teams.
I did find this information in my research
Prior to the invention of infrared image converter tubes a method
was needed for signaling between ships which couldn't be seen with the
eye. The metascope used a ~6" Schmidt f/0.5 mirror & corrector to focus
infrared light onto a screen made of a substance which could be
"charged" with blue light then it would convert IR into the visible band. The
charger consisted of a small lamp and four AA batteries. I don't know what the
conversion material was, but it had a curved surface to match the focal
plane of the Schmitd optics and light salmon colored, made of fine crystals.
There may have been other models from the one I just described which used
the same principle.
I believe they were used with a special transmitting lamp as I've seen
cesium lamps which were used for signaling. I think these were used
together. I also believe some of the early devices with the 1P25 image
converter tubes also carried the name metascope. Compared to a modern
GenIII image intensifier these devices were very insensitive but they
got the job done.
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