NavList:

Hello Francis,

It is nice to hear that you liked the diagrams. Also good that you pointed out the paper by Lyukx, I had missed that one. Now I got a view of the rotor on the other side also. I wasn't sure which way it is flipped, but now that is clear. There is no problem in creating the diagram for the other rotor also.

Lyukx gives a different description about how the device is used compared to Brown and Nassau. According to Lyukx the rotors are used twice, first to find altitude, then again using altitude to find azimuth. In the description in Brown and Nassau both altitude and azimuth are found in a single step. The rotors shown in the Lyukx paper and in the photo of the device in Smithsonian are missing what Brown and Nassau call azimuth lines. I wonder why the difference. Perhaps azimuth rules became too complicated when the one-step approach was used?

The other things you mentioned are also certainly doable, like the verniers. It takes just some time to do them. I'll post updates of the diagrams, and also the program to create these.

Cheers,

Harri