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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
How to choose among position lines?
From: Federico Rossi
Date: 2003 Jun 11, 19:08 +0200
From: Federico Rossi
Date: 2003 Jun 11, 19:08 +0200
Hallo everybody,
I want to submit you a doubt I often encounter when
I draw position lines to find the position.
Usually, in the Italian merchant marine they used
to plot 4 position lines, aproximately 90° with respect to each other, and this
configuration doesn't leave space to doubt when it's time to draw the bisecants
in order to reduce the systematic errors.
The Americans used to be even more practical and
adopted 3 lines spaced 120° (obviously this in the ideal condition when you can
choose which bodies to shoot).
In "100 problems in Celestial Navigation", which I
consider a very good exercise book and I advise to everybody, instead the author
often uses 5, 6, 7 or sometimes even 8 bodies, differently spaced in azimuth. In
this cases, are there general criteria to choose the lines to use (since the
choice can bring to significantly different positions)?
Thanks,
Federico Rossi
