NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sextant calibration accessory
From: Peter Monta
Date: 2021 Feb 27, 19:05 -0800
From: Peter Monta
Date: 2021 Feb 27, 19:05 -0800
Hi Frank,
By the way, back when I was messing around with this a decade ago, I recall reading an article from c.1905. The article proposed something like your concept of a set of prisms that a navigator could purchase and have available to re-calibrate a sextant on the "far side of the world". That's all I can remember about it right now. We may well have discussed it in NavList messages ten or twelve years ago. Just so there's no misunderstanding, I think the principle is sound. My only issue was that I couldn't make a practical implementation.
OK, great, I found the prior discussion on NavList, from 2014 and 2007. The British patent referred to in that discussion (link below), no. 316438, is from 1929, but if you find something from 1905 or thereabouts, that would be interesting to see.
At first glance, the method does sound like it provides arc-error data, but tied to the telescope line of sight, not to the index, so I'm not sure you get the stepping-stone feature from repositioning the angle reference. I'll look it over some more, though.
Cheers,
Peter
