NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Compass Rose
From: Dan Hogan
Date: 2001 Mar 24, 12:02 PM
From: Dan Hogan
Date: 2001 Mar 24, 12:02 PM
On 24 Mar 2001, at 8:59, Edgar Kitchin wrote: [Snip] > Then there is the system that one no longer sees which had the form "N > 45 E", "S 20 W" etc. for which I can't see any advantages but presumably > they some at sometime. > [Snip] The above system is the result of using "the Law of Cosines" formula for sight reduction. HO 208 and many of the pre-WWII short tables give the answer in reference to N/S__W/E of the quadrant. These required memorizing a set of "rules" to use them. Let L= latitude h= altitude d= declination Z= azimuth t= local hour angle h= sin<-1> (cos L x cod d x cos t + sin x sin d) Z= sin<-1> (cos d x sin t / cos h) The above formulas can be worked with an pocket calculator or, if you really want to work, with a set if Trig Tables. Most are described in pre- 1995 navigation manuals. Dan Hogan WA6PBY Catalina 27 "GACHA" Navigation-L List Owner dhhogan@veriomail.com