About our newly swopped
Infra-Red optical system
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: 13 May 2021
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.
Stefan Baumgartner offered me to improve our former, rather clumsy, drawing combination (12 May 2021)!
I hope you like it as we do.
Please click at this drawing as to open it in PDF
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