NavList:

Mark

Congratulations on your enthusiasm.  You can have lots of fun with a sextant.  However, I’m probably teaching Grandma to suck eggs, but be aware that you’ve been watching an excellent video describing the use of a marine (two mirrors) sextant recommended under the title “A10 A Sextant Repairs”.  The A10 A is a bubble sextant built initially for use in aircraft.  There are significant differences between the two such as the situation they were designed to work best in, the accuracy you might expect from them, and if you were thinking of buying one on eBay or similar, the chances of not being disappointed with your purchase.  Most bubble sextants advertised on the net were put into someone’s roof at the end of WW2 and have been recently found by their relatives.  They tend to be stiff or even jammed, dirty to look through, and bereft of any chance of forming a bubble.  Sometimes the original owner will have left batteries inside from 1945, so there might also be corrosion.  That’s not to say there aren’t good ones around from the better auction houses or from a collector, but they tend to cost considerably more.  Neither is it to say that that the tired ones aren’t good fun to work with, but if your interest is shooting good astro immediately rather than being fascinated by the WW2 instrument maker’s ingenuity and the wonderful (tobacco and alcohol) smell when you first open the box, best stick to a marine sextant first time around.  Dave

Re: A-10A Sextant Repair
From: Mark Richardson
Date: 2014 Dec 27, 03:27 -0800