A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2018 Dec 2, 08:59 -0800
Bill Lionheart, you asked:
"On this subject of terminology can I check what you call the result of averaging a series of sights of the same body? Is it still called a sight?"
I suggest that we stick with plain language whenever possible, so I call that "the average" or "an averaged altitude" or "an average of sights". It doesn't need a new name.
Speaking of altitudes, one of the most common cases of jargon confusion in celestial navigation comes from the shorthand names used in sight reduction. We have Hs for the "raw sextant altitude" and Ho for the "corrected sextant altitude" and sometimes we even throw in Ha at an intermediate stage. These "names" are about as obscure as they could be. You have to learn the names eventually, at least Hs and Ho, to follow the literature, but training beginners to "talk the jargon talk" should be a low priority. Save it for later if possible. It's much more comprehensible if we write these out in a bit of "longhand": write out "raw sextant altitude" and write out "corrected sextant altitude" when possible.
And then, of course, there's the symmedian point. This is a dreadful name, but if we want to discuss the concept mathematically, that's it --that's the standard name. There's no significant alternative. Myself, I have never once used the phrase "symmedian point" in a class for beginners since it covers only a limited case: the three-body fix with equally weighted sights and no systematic error. This is not worth the time, and --even though it sounds less technical-- I also never define the "cocked hat" since that's just a weird name for something simple. We need the latter name to follow the culture of navigation, the coded conversations of the subject (english language navigation culture), but not to understand the subject and principles of celestial navigation itself.
(I originally wrote per se for "itself" but that's its own sort of jargon... going Latin is a bit passé... uh-oh... per se is passé??)