A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2016 Mar 17, 20:42 -0700
Thanks, everybody, for your ideas so far ...and please keep them coming. I am quite serious about this.
I considered many of the options you've described over the past few weeks. I was hoping for something with Classical Latin or Greek roots like the ideas that Magnus Sjoquist proposed. But there's just too much "giggle factor" on anything with sex in it. See how quickly we got to "sex-agree" and Bill B's very clever "nauti-sex" --terribly naughty! In addition, words in this category are often difficult tongue-twisters easily confounded with other technical terminology. Many times I have heard people learning navigation, who also know some digital tech, confusing the words "sexagesimal" and "hexadecimal". And neither is anything more than annoying trivia for most students of both subjects.
Don Seltzer, I really like your suggestion, and it comes closest to creating a term that would have flowed naturally from English-language navigational culture. Either "league-score" or "score-league" could both easily define 60 nautical miles. I had even got as far as considering something like vigint-leagues, but "score" never occurred to me. My original choice, and maybe still the best, was the one also suggested by Brad Morris, "nautical degree". But it doesn't really work in the same way that nautical mile distinguishes itself from one minute of arc.
The idea here is to tie together, in teaching, the relationship between altitude and distance on the ground to the substar point (also known as the body's "GP"). Distances are not measured in degrees. They're measured in distance units. And if you say, we don't need that!, then one could as easily argue that we don't need nautical miles. And we don't. They're stupid! ;)
What would this have been named if the metric angular units had caught on? A right angle was supposed to be divided into 100 grads, and each of those grads was divided into 100 centigrads. The "centigrad" angles have their corresponding linear distance unit. It's the kilometer. There's probably some horribly mangled combination of prefixes, like a hectokilometer (?), but I wouldn't be surprised if the designers of the metric system intended to have an efficient name for one "grad" measured across the Earth's surface -- the distance unit to accompany the angular unit.
Thinking aloud again, how about "surface degrees"? Or "Earth degrees"? I hate acronyms, but how about calling them DOGs... for "Degrees Over the Ground"? Woof!
By the way, my thinking on "nautical delta" which I mentioned earlier today is that the "d" of delta would represent both 'degrees' and 'distance' and a shift in position is often called a "delta" as in the mathematical sense of delta-x. So a "nautical delta" would be a shift in position of 60 nautical miles. And delta has the advantage of being easy to pronounce, relatively international, and not tied to much of anything else already used in navigation. But there's also no hint in it that directly says distance, in the way that "nautical mile" announces itself as a distance unit.
Let's try this in practice. The cleared altitude of a star is 60° 20'. I convert that to a zenith distance, subtracting from 90°, and get 29° 40'. This immediately implies that my distance from the substar point is "29 nautical deltas and 40 nautical miles". It's a physical distance measure along the ground that corresponds to the angular value. Since we "know" that 90 nautical deltas is a quarter of the way around the globe, regardless of direction (because it's along a great circle), we can readily picture that.
Brad, you worried that such terminology is not in the reference books: that's proof that you worry too much about reference books! Ha ha. :) Besides, how do you think all that terminology got in the books in the first place? :)
Conanicut Island USA