Friend of mine in Glasgow bought a house that came with a garage full of old car bits. The nice car bits got sold.

There were odds and sods left… amongst them this massive glass magnifying thing and some gigantic 2 foot spanners which my friend let me take…because I hoard random stuff like that, just like the old man who owned the garage before selling his house to my friend.

I don’t know why I took it… but I have had it for 15 years now and how no idea what it’s for or what to do with it. I take it out now and then, look at it, and put it back on the shelf.

There’s a round metal frame/collar that holds two half convex lenses apart. They’re ground flat on the outside. There’s a little hole where you could poke something in… (a bulb?). Then there’s a loose lens that sits on top… or perhaps the loose lens is a spare. Is it part of a telescope? periscope? lighthouse lantern? anyone seen anything similar?

Looks like a Potty. Used by the navigator to read maps on night stage rallies. Did it have a light inside it>?

Lamp maybe used to be fixed through the hole? Possibly an early homemade example before Don Barrow started selling commercial versions

https://donbarrow.co.uk/map_magnifier_db2/

Might be a lens from a theatre light

Photographic enlarger condenser lense.

I think.

Based on I have a similar one in… A photographic enlarger.

Infact… How big is it. Diameter wise

To clarify.

It’s definitely a condenser lense but it might not be from an enlarger. Microscopes use them too.

All interesting suggestions.

There was no light in it at the time. The hole on the side  is only an inch in diameter so it would have to have been a really small bulb, hence why I’m uncertain about that.

It feels like it would slot into another tube shaped object with the collar holding it in place.

The old man tinkered with Jaguars/Daimlers and that was what all the car parts were. Possibly part of some ancient headlight? The whole thing is massively heavy due to all the glass.

I’m thinking early headlamp. Something like this

Thanks Josh… I’ll do some googling in that vein.

Still not sure what I’m going to do with it even if I find out what it is!

In an enlarger it would do exactly what you think, it would sit in a pressed metal cup or sheet metal box in a circular hole. The lip stops it falling through. The small hole would probably just be a latch to keep it in place.

Then you have the negative then you have the enlarger lense with aperture control on it.

So if you Google enlarger lens you will get loads of things that look nothing like what you have.

The simplicity of it, I am guessing soviet. My meopta is a bit more engineered but very very similar in dimensions and even has one loose one and one captive like that.

infact… How big is it. Diameter wise

It’s just under 12inches in Diameter. Biggun…indeed it does look a lot like and enlarger condenser now that I’ve searched that angle.