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
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.