I got this interesting lens in a simple tube mount, no shutter and no aperture but I find it worth to mount it in a shutter.
I messure the dimensions and realise that only a shutter with the size of the Compound IV can be use.
For this I bought in England an Wray Lustrar 300m f/5.6 which has to leave the shutter, sorry.

The thread of the lens don´t fits to the Compound shutter and this means to machine it.
The shutter cell mount has a unique thread, it has a metric diameter of 67mm but an imperial pitch of 40g/inch and a flanc angle of 64° which is not a standard in any kind. So I have to grind a tool for to cut the thread.

Now you can see that I realised it, the lens is mounted in the shutter with the high precision which is necessary.

This Orthostigmat is a Plasmat design, six elements in four groups, it is a late Steinheil lens, the serial # is over 1.7 mill.
It has a thin blue magnesium oxyd coating.
The angle of view should be larger that 75°, only this makes sense when the glass diameter is so large.

I guess it is more a collectors item, I´am sure it is the only one that exist. In the lens makers vademecum is written that a 240mm f/4.5 lens maybe were made but no one saw it, this 210mm is not mentioned.
The most popular Orthostigmat in a similar optical design is the 35mm f/4.5 for Leica M39 thread mount.

When someone has any further information I will be glad to get it.