A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2020 Sep 7, 16:11 -0700
Al Stewart, you wrote:
"I carefully unscrewed and removed the perspex cover to look at the certificate, and found there were two older ones behind it dated 1954 and 1939!"
Nice! I'm amazed that the old certificates were there.
"another article online https://sextantbook.com/2009/01/03/evolution-of-the-sextant-micrometer/ states..."
I just wanted to make sure that you have noticed that the author of the sextantbook.com website (and author of the excellent related book "The Nautical Sextant") is Bill Morris --the same Bill Morris who replied to you here. :)
Are you still interested in scope collimation? There's no mystery to it really, and there are two general ways to do it: one by direct observation through the instrument, though it's a little tricky and another (really a whole class of methods) by tabletop optics. I, or anyone else here (feel free to jump in), would be happy to discuss this further. But perhaps you're satisfied you don't have to worry about that anymore...