A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2016 Apr 18, 18:52 -0700
Roger Connor of the National Air & Space Museum, Smithsonian Institution, has provided a photo of the "other side" of the Brown-Nassau spherical triangle calculator. Francis Upchurch, I believe you've been looking for a view of this for a while?
There was already a photo of one side on the Smithsonian's site. I've merged the two together. You can see in the combined image below that the rotating overlay on one side has red curves with a pole at the top while the overlay for the other side has blue curves and its pole at the bottom. The verniers on the front/back (red/blue) overlays are also labeled differently, which is key to deciding the various cases of the triangle solution. The base plate is the same on both sides as near as I can tell.
Conanicut Island USA