It is possible to make an estimate of the right size Derogy. A focal length of 65cm, F4 gives a lens diameter of around 16cm. Probably 1 or 2 sizes up from the recent 262256264385 which has 12cm diameter lenses and is 31cm long.
That there were 4 additional lenses and the engraving was obvious experimental suggests it was a special order.
So I have no illusions as to finding the parent lens or even being able to afford it!
If there is an owner around, he/she is very welcome to get in touch.
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