NavList:

Greg,

Looking closely at the SI photographs, and reading between the rather vague  and incomplete lines of the Luykx paper, it seems that one side has a rotor with verniers A and X (as on the SI photo), and the other side B has the rotor going the other way with verniers B (see Luykx) and presumably Y instead of X. So maybe the verniers increase the accuracy? You choose which side A or B according to the index.

Anyways, what I really need to make a replica is an accurate full sized scan of both base plate grids with the rotors moved out of the way and accurate scans of both A and B rotors. It should be reasonably easy to print them on plastic sheets.

I guess the best way to get that would be to go see the thing at the SI (however, it is not on display but   either on loan or in storage). I have emailed SI and asked for scanned  high quality photographs as above.

If anyone lives near the SI and fancies taking a look, please let me know. I’ll give you my wish-list!

The SI website states that they lend out items to other bone fide museums etc. I wonder whether Frank’s Mystic Seaport planetarium  could borrow it?

Just a thought.

Francis