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.

The image referencing "Haussystem Didot" is an example of a catalog not containing the Angzarr symbol in question.

I did not find any evidence for earlier examples in any of the very few scans I looked at, nor does a search through the Google Books scans give any indication for words that seem related to the concept.

This would be such a fantastic find! Could you point out a specific example?