Fascinating links, but I could not find an example of the glyph in question? My point was that a sextant is not (and cannot be) used to measure azimuth. It primarily measures the angle between a celestial body and the horizon (i.e. altitude). It can also (theoretically, very rarely) be used to measure the horizontal angle between two or more landmarks, but that is not azimuth in the accepted sense of the word. I am happy to be corrected though; my experience of sextants may be too narrow or modern for this context.