# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Plotting on graph paper
From: John D. Howard
Date: 2019 Oct 1, 07:55 -0700

Frank,

Thank you for the information on the time sight.

Near the end you wrote:

"And there are plenty of other options that bridge across these possibilities. For example, you can calculate a single time sight to get one point on a line of position, and then you can use azimuth tables (or graphs). You then draw the line of position through the single position perpendicular to the azimuth. Note that there is no "intercept method" in this anywhere, yet it makes use of some of the more modern tricks. This technique unfortunately throws out one of the great advantages of the two-point (Sumner) calculation of the line of position, which is that you can plot it on common graph paper or equivalent, no special plotting sheets required."

Why not plot an intercept on common graph paper?  I use graph paper to plot and seem to do OK.

I call each line one mile.  Put my AP in the center, use a protractor for azimuth.  At the small scale - plus or minus 60 miles there should not be much distortion.  Only after I plot two ( or more ) LOPs and get a x or triangle do I need Lat and Long.  Delta Lat. easy: miles equal MOA.  Delta Long almost as easy:  miles divided by cosine Lat is MOA.

Am I doing something wrong?

John H.  41N  100W

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