[PenPusher]

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Not sure if this is the right spot for this message but it must use some kind of film / recording media.

On e-bay there is what looks like a demo model of a three direction Nuclear Pinhole Blast Detection camera, it seems light entered through one of the pinholes making a recording on a grid from which you could work out where the blast took place, just the thing for your own personal bunker.

Started at €400 currently at €1750

Below is the best I can do, not very good at links so paste this in to your browser

Very rare Nuclear pinhole camera Radiac Ground Zero Cold war Royal observer corp | eBay

[AstroDave]

Love this comment in the listing: "Apart from that I cant see any damage."

Must not have been too near to any nuclear event!!!

[StiffLegged]

If the blast was reasonably near, plain paper might suffice as the light intensity might be enough to singe the paper. Alternately, if too close all paper might as easily ignite (451 degrees fahrenheit, as I recall...)

[HoutHans]

I'd rather spend my 1750 on something else than this camera that I'd hope never to use.

[WillWeaverRVA]

Well, in the event of apocalypse, I know where to find one of these!

[disconnekt]

I'm sure at that price, it must be... the bomb! Lol

[Gerbermiester]

Neat, but wowza that price.

[kiwi_jono]

Interesting, this had me looking up what sort of photo sensitive film they used... found a little more info at camera, pin hole, ground zero indicator | Imperial War Museums

I'm now assuming only worked in close proximity with light so intense it basically burnt any (even non photographic) film.

---------- Post added 10-12-2019 at 09:14 AM ----------

Oh I forgot to add, at €1750 this is pretty expensive but with this thing you will have a blast.

[Apet-Sure]

Any chance it was near a nuclear blast during certification testing before originally being sold? I'd check it with a geiger counter!

[photoptimist]

If the blast was reasonably near, plain paper might suffice as the light intensity might be enough to singe the paper. Alternately, if too close all paper might as easily ignite (451 degrees fahrenheit, as I recall...)

That's probably what it did unless they either replaced the photosensitive paper every day or used somethng with severe reciprocity failure so it would not eventuallly fog with exposure to day light.

It may be a variant on the https://en.wikipedia.org/wiki/Campbell–Stokes_recorder that records sun intensity by letting a spherical lens burn a track into a sheet of special paper. The paper is treated so that it can't ignite but will char to show when the sun was shining.

[PJ1]

Interesting concept and piece of equipment. It must have used special photosensitive paper. Surely if the blast was near enough to char plain paper the direction would be not be relevant.

[Not a Number]

From the IWM pages:
(describing one of the films/videos (missing)):

The three man team arrive at their ROC monitoring post, a bunker located down a shaft. The film shows how the bomb power indicator (BPI) is set up, and how the ground zero indicator (GZI) is prepared by pre-exposing several sets of "printing out paper" charts with a grid, the first set being placed in a pinhole camera device mounted above ground. In a simulated attack, the BPI reading is taken (logged on a form dated 31/9/84

I doubt this unit was ever near a nuclear blast. The Nuclear Test Ban Treaty which banned all but underground nuclear detonations took effect Oct. 1963. And if you were conducting an above ground test it seems to me you would know what direction ground zero was from any observation post.

Definitely a museum display piece. The red painted edges on the cutaway portion seems to be convention. The tanks that had cutaways in the Imperial War Museum that I saw were all painted like that.

[g026r]

That's probably what it did unless they either replaced the photosensitive paper every day or used somethng with severe reciprocity failure so it would not eventuallly fog with exposure to day light.

It may be a variant on the https://en.wikipedia.org/wiki/Campbell–Stokes_recorder that records sun intensity by letting a spherical lens burn a track into a sheet of special paper. The paper is treated so that it can't ignite but will char to show when the sun was shining.

Another line from the film that Not a Number posted the description of, it sounds like they were in fact using photographic paper:

A team member demonstrates blindfold the routine changing of the charts (needed up to twice a day in the summer due to exposure from daylight).

[clickclick]

And who was going to come develop it after the blast?

[PenPusher]

O8.25 GMT now at €1,805, to be honest I didn't think anybody would bid for this thing but there still seems to be some interest.