NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: UNK
Date: 2014 Dec 3, 19:00 -0000
Thanks Harri,
That is great. However, I may be missing something here, but rotor A looks as if the Y axis numbers 0-90 are going the wrong way? May be my mistake.
Thanks again.
I will start a new build as soon as we have sorted this.
Best wishes
Francis
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Harri Ojanen
Sent: 03 December 2014 16:31
To: francisupchurch@gmail.com
Subject: [NavList] Re: Brown-Nassau Spherical computer
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
Attached File: 
(brown_nassau_dots1.pdf: Open and save or View online)
Attached File: 
(brown_nassau_lines1.pdf: Open and save or View online)
Attached File: 
(f1-brown_nassau_lines2.pdf: Open and save or View online)
