NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David C
Date: 2024 Jan 5, 19:00 -0800
This does not answer Frank's question but in 1921 the US Bureau of Standards required that a sextant have a "long" telescope with two eyepieces giving magnifications of about 6x and 10x. A short telescope provided about 3x magnification.
Circular 110 Specifications for Marine Sextants.
https://www.govinfo.gov/content/pkg/GOVPUB-C13-1ad5b7d1264f864b0dbe5aaf881fbf84/pdf/GOVPUB-C13-1ad5b7d1264f864b0dbe5aaf881fbf84.pdf
The Admiralty Manual of Navigation (AMN) states that the largest power telescope should be used when checking a chronometer on land using an AH. Is this relevant to Frank's question? I do not know.
An advert in the 1928 vol 1 edition of the AMN shows that in that era Husun were manufacturing sextants with 10x magnification.
Finally to reveal my ignorance. There is a current thread about Husun sextants. I wondered if it was a Japanese brand - was it pre or post war? Then when I was studying the 1928 advertisment I realised that Husun is a contraction of Hughes & Son!!!!!!!!!!!
