NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Harri Ojanen
Date: 2014 Dec 3, 08:30 -0800
Hello Francis,
Here are new versions quite close to the one in SI. Verniers and additional scales are now included. Actually the verniers in the SI model are quite subtle: they seem to be printed on top of a strip of white paint. Along the arc on the base plate there are two scales, one going from 0 to 90, and the other going the opposite direction. The white background of the vernier on the rotor always hides the scale which is not to be used with it. A nice way of preventing errors happening by using wrong combination of scale and vernier.
Well, most printers don't have white ink, so I can't reproduce that. (Actually years ago I had a dye-sublimation printer, and there was white ink available for it - used when printing on colored paper. Similar devices might still be available, though probably quite rare.) For now one just has to be careful of using a scale and vernier combination where the numbers increase in the same direction on both.
Harri
