NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Another "emergency navigation" sight reduction method
From: Hanno Ix
Date: 2015 Jul 12, 12:00 -0700
The cot() scale - partially shown in the attached picture - proceeds around 45 deg in steps of 10 arc min. So in this area of the scale any visually interpolation of 2 out of 5 without further reference is rather subjective. And this is the reason of my statement above. It could very well the biggest error component of your design!
That actually is a shame. By re-designing the set of marks you are using and including marks for 2 min steps ( e.g round dots ) you could increase the utility of your Flat Bygrave significantly. From my experience with making scales this is not too difficult, there is sufficient space for them.
H
From: Hanno Ix
Date: 2015 Jul 12, 12:00 -0700
Gary,
your claim of 2 minute or better accuracy is hard to contradict - and equally hard to confirm.It also would make it possible to prove your claim.
On Sun, Jul 12, 2015 at 6:26 AM, Gary LaPook <NoReply_LaPook@fer3.com> wrote:
The cotan scale on my flat Bygrave is only 10 inches long by 7 inches high and I get 2 minute or better accuracy. The cosine scale is smaller. They each fit on standard 8 1/2 by 11 inch paper and clear plastic sheets.
gl
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