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From: Paul Hirose <cfuhb-acdgw@earthlink.net>
Subject: [NavList] slide rule sight reduction accuracy
To: "Google nav list" <NavList@fer3.com>
Date: Sunday, April 8, 2012, 1:51 PM

Lu Abel wrote:
> My view, though, is that slide rules, while useful for almost all engineering calculations (anybody want even a 1% margin of error on safety calculations?), celestial requires calculations 1000 more times accurate.

I looked into that matter a few years ago. With a Monte Carlo simulation I found that an ordinary 10 inch rule, working the Bygrave formulas, should be accurate to 1.8' in altitude. That's the 1-sigma error, i.e., about 2/3 of the results should meet that standard.

Thinking that figure too good to be credible, I worked a few problems by hand and confirmed it.

http://fer3.com/arc/m2.aspx/Bygrave-formula-accuracy-on-10-inch-slide-rule-Hirose-jul-2009-g8985

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