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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Traditional navigation by slide rule
From: Brian Walton
Date: 2024 Aug 12, 18:03 -0700
From: Brian Walton
Date: 2024 Aug 12, 18:03 -0700
Whilst messing with a simplex Pickett trig slide rule with a somewhat loose cursor, I found I could insert a piece of paper between the rear face of the rule, which only has instructions on it, and the cursor. There, was a blank slide rule.
A 'P' Pythagorean scale is desirable, as is a ST scale. I found and photoed a Darmstadt- style face with those scales, and printed off a copy, which was spray-glued to the rear of the Pickett with the slide removed. The rear of the cursor had no hairline, but colouring one edge with an indelible pen sufficed.
The P scale and larger lettering greatly improve obtaining cosine values for smaller angles, and thereby the working of a Bygrave solution.
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