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posted to rec.boats
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Sun Compass Skills
"Wayne.B" wrote:
The sun compass. This instrument draws on the fact that the sunīs
shadow from the tip in the middle of a disk describes different
hyperbolas at different times of the year. When you have the hyperbola
representing 62° and the four weeks around summer solstice, you donīt
have to know the time of the day in order to find the general
directions. All you have to do is rotate the disk until the shadow of
the tip falls on the hyperbola, and the general directions are given
with an accuracy of a few degrees. One of the ingenious things about
navigating with this instrument is that if you should choose the wrong
gnomon curve and get a course that is a little too much north in the
morning, this will be corrected in the afternoon by a slightly south
bound course-and your average direction will be correct.
Another simple method:
http://tinyurl.com/aub5l
--
Skipper
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