A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Henry Halboth
Date: 2010 Feb 5, 18:15 -0800
For what it may be worth, I have worked your Longitude at Sunset/Sunrise problem by the old fashioned conventional method, i.e., the Time Sight, utilizing the following data:
July 1, 2009; Latitude 17 degrees North; ZT (+9) of Sunset (LL) 18-58-26, and come up with the following:
At ZT 1858
Longitude 129-26-16 East
LOP running 205/25 degrees, through posit 17 degrees N x 129-26-16 E
Potential error in Longitude/1 degree error in Latitude = 0.5’, applied (-) for error to south and (+) for error to north. Thus if the Latitude was actually 16-30 N, as has been suggested, the calculated Longitude would be in the order of 129-11 E, which should then also fall on the fg LOP at 16-30 N.
Should you be stationary, or making but little way, you
might be able to X this with a subsequent Sunrise LOP to obtain a reasonable
fix. This is something for you to try at anchor, with a view of both E/W horizons.
To work this method, you of course must have a logarithmic table of trigonometric functions or an appropriate calculator, in addition to a Nautical Almanac, and who is to say what you will or should have in any emergency situation – perhaps it all boils down to a matter of advance preparation consistent with your individual level of competence.
--- On Thu, 2/4/10, Anabasis75@aol.com <Anabasis75@aol.com> wrote: