NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: St Hilaire not Iterative was: Finding The Symmedian
From: Jeremy C
Date: 2010 Dec 27, 08:29 EST
From: Jeremy C
Date: 2010 Dec 27, 08:29 EST
Andrew wrote
"I will try to explain.
A navigator using plotting techniques introduces greater errors
which stem from these techniques (placing a ruler, drawing line along its
edge are not exact operations, especially on a small cluttered badly lit
table which rocks back and forth). Assuming your AP is within a degree,
the error introduced by Hilaire method would be smaller then the errors
introduced by the act of plotting lines. Doing second iteration would be
a waste of time."
A navigator using plotting techniques introduces greater errors
which stem from these techniques (placing a ruler, drawing line along its
edge are not exact operations, especially on a small cluttered badly lit
table which rocks back and forth). Assuming your AP is within a degree,
the error introduced by Hilaire method would be smaller then the errors
introduced by the act of plotting lines. Doing second iteration would be
a waste of time."
---------------------
I second this Andrew. The vast majority of my error come from manual
plotting when I choose to do so. I am just not accurate enough in my
plotting to do justice to my observations and the mathematics. My pencil
lead is certainly greater than 0.1 degrees wide in AZ column and I can't get the
intercept measured on standard plotting sheets better than 0.25 nm for the most
part using my triangles. Heck, I can't even plot the
advanced/retarded AP's accurately enough for my tastes.
This is one of the major reasons why I use computers to give me a fix and
then just transcribe the given fix as a Lat and Long to the chart. It is
also much neater on the chart which makes the Captain happier.
Jeremy
