About our newly swopped

German

Infra-Red optical system

 

FG 1250?

Why using here a question-mark?

Because it is not entirely unlikely that our new device may be of a type in the FG 1240 - 60 series, though we don't know yet exactly the according number type-number.

Therefore I would like to start-up a brief Survey. 

 

Page initiated on: 17 December 2018

Current status: 18 December 2018

A

 

 

(A)

Our just unpacked FG 1250 infra-red vision apparatus

approx. length is 460 mm

 

 

The red label, originates from one of the former possessors

 

 

Through this lens once the IR image was viewed

We will later learn, that for some occasions a special loupe arrangement could be fit onto it, likely to magnify far-off targets.

 

 

The front section of our IR vision device

Lens diameter: ca 111,7 mm

The black system is an (prism) arrangement, where a light-spot being provided in the centre of the IR display; this is creating a light-spot on the vision side; for us just on the opposite of the vision system.

This might be crucial, as its aim was hitting a target in the complete darkness, and then you should be able to aim precisely.

 

 

Viewing it just a tiny bit differently

 

 

Vor Sonne schützen !

(do not allow an exposure of sunlight)

The cathode just after the front-end lens-system, is responding onto the infra-redlight-photons; these are exciting electrons which will travel into a cylinder where its speed being increased due to a voltage trajectory (12 kV) which differs from the start up to just before it excites the phosphoric-screen, and has converted the for our human eyes invisible infra-red photons into for humans visible, I guess, likely green image (but it could also be yellow). This picture is being magnified by a quite complex lens system.

 

 

We have to apologise for this clumsy drawings compilation, but it quite well shows what the internal FG 1250 is technically about

 

 

This lens (on the operator's vision side) consist of a range of lenses in series

 

 

Pz.Gr. 39/42 and Spr.Gr. 42 is to the preset the type of grenade used at the moment

Panzer Granate (anti-tank grenade) and Spreng Granate (an anti-personal grenade type)

 

 

Particularly interested in the mounting plate, which in my perception is a genuine provision.

 

 

The number 300 might not be a serial number but likely originating from the production process

 

 

The HT connector upper outside diameter 370 mm and internal 216 mm

It should be fed from a 12 kV voltage source, which we do not yet possess.

 

 

This photo shows how the FG 1250 apparatus series once had been mounted on a half-track

This half-track had been fit for night operations; the lower IR vision device allowed driving the vehicle without recognisable light; and the upper arrangement was meant for night combat.

Please notice the two infra-red light-sources.

 

To be continued in due course

 

 

By Arthur O. Bauer

 

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