NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Rust's diagram for computing azimuth
From: John Cole
Date: 2007 Oct 09, 16:20 -0700
From: John Cole
Date: 2007 Oct 09, 16:20 -0700
In an earlier time Burdwood's Time Azimuth Tables were used extensively to correct the compass and for other purposes, indeed according to the preface of my 1940 second revised edition "for fifty years Burdwood's Tables have been known and used by every seaman". The full title is "Sun's True Bearing or Azimuth Tables." Those who learned navigational astronomy from Smart's venerable "Spherical Astronomy" or his wartime "Handbook of Sea Navigation" will be familiar with them. On Oct 8, 1:42 pm, Gary LaPookwrote: > Gary LaPook writes: > > Attached is Rust's diagram for computing the azimuth of the sight which > was included in Weems "Line Of Position Book," 1927. It was developed > using the sine formula. You enter on the left with LHA and go to the > right to the declination then straight up to the altitude then to the > right to the azimuth. Also included is a table used to determine in > which quadrant the azimuth falls when the body is close to east or west. > This diagram can be used with any set of tables, H.O. 208, H.O. 211, > etc., and the extra steps used in those tables to compute the azimuth > can be disregarded. > > The shape of these curves show the potential loss of accuracy using the > sine formula as the azimuth approaches 90� as the altitude curves become > almost vertical and only slight changes in altitude results in large > azimuth changes. > -- > > Rust diagram.pdf > 206KDownload --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---