A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2014 Jun 11, 10:24 -0700
See the RIC which uses a 10" slide rule for the single multiplication. The same reduction on a 10" slide rule using the standard sin cos formula doesn't work out as accurately. Bygrave formula also beats the standard formula using a 10" SR. At my latitude the 10" SR seems to be good enough (2') for various ranges of declination and LHA by Doniol formula. There is always the longhand multiplication to get complete 4 place results for 1' accuracy if needed. Reduction times are quick and quicker either way.
Attached is also a summary of formula with rules. There may be additional rules.
I'm thinking that an LTA, Cos Sin, HavSin, and Diagram booklet can be done in fewer than 8 pages.