A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2017 Sep 25, 11:52 -0700
Rating the cylindrical slide rules for SR (1. excellent 2. very good)
1. Bygrave ... hard to finding and expensive.
2. Fuller... expensive.
2. Otis King ... available at reasonable cost used. Good to four place precision using law of cos trig formulae and four place natural trig tables.
Conventional slide rules and circular slide rules have only 3 plave precision so not good enough for calculating Hc but good enough for calculating azimuth.
PS Requested PDF Hav tables attached: 1' table is most precise, 2' table is good enough, 10' table is a neat one pager for wallet but does require interpolation.
From: Tony Oz
Date: 2017 Sep 25, 07:37 -0700