Two On A Big Ocean The Story of the First Circumnavigation
of the Pacific Basin
in a Small Sailing Ship


      

Other Books by
Hal Roth
| Home | Mailing Lists | Bookstore | Weather | Tide Predictions | Bowditch |

Re: Variation of compass


Subject: Re: Variation of compass
From: Michael Wescott (wescott_mike@XXX.XXX)
Date: Thu Oct 03 2002 - 13:25:22 EDT


daveweilacher@XXX.XXX said:
> One thing I attempted was to compute compass variation by assuming a
> GP for the mag north pole of 82N x 108W then doing a sight reduction
> to obtain azimuth (Zn).

> Ended up deciding there were two problems with this; both biggies.

> First, it ignores the earths own magnetic anomolies. No help for this.

> Second, it gives me an initial great circle bearing when I suspect
> what I'm really after is a rhumbline bearing.

Great circle is what you want, much the same as a fix on a radio beacon.

--
        Mike Wescott
        Wescott_Mike@XXX.XXX





| Home | Mailing Lists | Bookstore | Weather | Tide Predictions | Bowditch | Trawlerworld |