NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The term AP
From: John Karl
Date: 2015 Jan 21, 14:40 -0800
From: John Karl
Date: 2015 Jan 21, 14:40 -0800
Gary L & All,
Yes, most (perhaps every) CN book that I've seen either does not clearly, or accurately, describe the role of the AP in the intercept method. Many alude to it being an approximation of some type, or even saying that "it's an approximation we wish to correct, or adjust in accuracy." Some say the AP is an approximation surrounded by uncertainty. Of course, that's true for the DR, but not for the AP. Also, some time ago when St. Hilaire was discussed at length on the NavList, a well-know member discribed it an an iterative calculation. Even my two editions of Bowditch only precriptively instruct performing the St. Hilare sight deduction with no discussion of why the AP is used.
J Karl
