NavList:

 I have  various volumes of the AMN from 1914 to 1964. In none of my volumes does it give the details quoted from the 1997 Vol2 edition. It seems that sometime from the 1970s onwards an AMN auther has decided to clarify the information about telescopes. Note also 1997 was well into the GPS era and sextant manufacturers were  probably no longer competing with each other.

This leads me to the following hypothesis using digital cameras as an analogy. In the early years of digital cameras a sales pitch was the number of mega pixels. What the manufacturers did not tell you was that the more pixels the smaller they were. And the smaller the pixels the less light sensitive they were. In other words the number of pixels was not necessarily a good measure of camera quality. But the man in the street did not know that.

Therefore in the early 20th century was the size of the telescope a measure of sextant quality?  One with a 3x scope cost $x and one with 10x cost $y where y > x. If you wanted a good sextant then why would you not spend $y? What the  manufacturer did not tell you was that the 10x scope could only be used on terra firma with a tripod.

A while ago Frank  suggested that advertisments were a good source of information. Sextant advertisments may be a good source of research.

David C