A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2016 Oct 13, 11:46 -0700
I was going to say the same thing. The NA is for navigators on the sea and the accuracy of the derived data is comensurate with the required level of accuracy and with the obtainable accuracy using a sextant. Also consider the response that another source of inaccuracy is the number of interpolations and adding a ".v" correction introduces another interpolation. There are a number of correction tables where corrections are combined where greater precision is dispensed with in order to simplyfy the process, just look at the moon and sun correction tables. In addition to intrducing additional inaccuracies with additional interpolations, each operation carries the risk of a "blunder" a large mistake (added instead of subtracted, value taken from wrong column) by the navigator, working in a dark cabin, being tossed about by the waves. In the past the NA used different formats and did include some of these corrections in seprate, more precise, tables but the present format evolved as the best all-around way of presenting the data for marine celestial navigators, not surveyors, for whom a different almanac was published.