NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2019 Feb 12, 22:16 -0800
Hi Alan.
Correct, as far as I know the only surviving known original is in the Smithsonian.
I built a replica a few years ago which works well. Only took a few hours at minimal cost. I think it would be easy to produce commercially if there was a market which I doubt. As far as I know nobody else from Navlist built one, so maybe there is little interest and mine is the only working example used regularly for CelNav. I find cylindrical slide rules such as the Bygrave and Fuller also relatively easy to build but more time comsuming and difficult than the BN.
Details of all my old builds are in the files somewhere. I do not know anything about the legal/copyright issues of commercial production.All my creations relied on others to provide the computerised scales and graphs.
Best wishes
Francis
