NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Wasting Away in Keuffel & Esser Ville
From: Hewitt Schlereth
Date: 2009 Jul 20, 10:53 -0400
From: Hewitt Schlereth
Date: 2009 Jul 20, 10:53 -0400
As part an eBay purchase of a K&E slide rule case which I wanted because it had the bulge for a magnifier, I got a 4090-3 rule. When I looked at the rule, I saw it's stator had Tangent, Sine (called S2) and ST (called S1). Its slide, though, only had [CF, CIF. CI, D] on the front and [B, K, CI] on the back. I wondered if a slide from one of my other rules with T, ST, S would fit this 4090. Turned out the slide from a 4070-3 [B, T, ST, S] did. I've found this saves steps in doing sine/cosine Hc and Az because it's not necessary to zero the slide at the beginning and end of each string of calculations. The problem I've had is not to look at the Tangent scale instead of the Sine scale(s). As you can see from the attached, the stator's T scale is directly under the slide's S scale, so my eye tends to fall on the T scale first thing. I'm now experimenting with various highlighters (on another really beat-up rule) to see if highlighting either the T or S2 scale will keep me from reading a tangent when all I want is a sine. Hewitt --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---