A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Mike Freeman
Date: 2019 Dec 20, 22:46 -0800
Your confusion may be as a result of my confusion.
My original post asked is the Mary Blewitt method of creating a homemade plotting sheet OK?
One of the several replies suggested the problem with the method was it created a chart of correct scale of the line drawn at an angle (say 54 degrees) and if your position ended up 53 degrees 30 minutes it will have been plotted on a chart of incorrect scale. I guess in this case it would be wise to draw another plotting sheet for 53 degrees 30 minutes. I don't think anyone actually challenged the accuracy of the method for the specific latitude in question.
I accept also that drawing some lines vertically and horizontally on a piece of paper does not consider any projection.
I attempted some calculations to try to determine for myself the errors introduced by the half a degree but am unable to analyze my own results.