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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Classification of the methods for clearing the Lunar Distances
From: Fred Hebard
Date: 2003 Apr 10, 20:20 -0400
From: Fred Hebard
Date: 2003 Apr 10, 20:20 -0400
Bruce, Perhaps my summary of Bowditch was inaccurate rather than the work itself. It said: "Davis' Requisite Tables, published in London in 1905, introduced the cosine-haversine FORMULA [emphasis mine] to navigation, although it had been used previously by astronomers. This formula is hav(z) = hav(L~d) + cos(L)cos(d)hav(t), in which z is zenith distance (90-h). This is sometimes written hav(z) = hav(L~d) + hav(theta), in which hav(theta) = cos(L)cos(d)hav(t)." A few pages earlier, Bowditch mentions that, "Early tables for solutions of meridian angle were called horary tables." I must add, in the same spirit as Herbert Prinz, that I much admire your work. Fred
