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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 LaPook < glap...@pacbell.net> wrote:
> 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 90º as the altitude curves become
> almost vertical and only slight changes in altitude results in large
> azimuth changes.
> --
>
>  Rust diagram.pdf
> 206KDownload