NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Paul Dolkas
Date: 2017 Oct 4, 19:21 -0700
I’ve run my A-12 with Isopropanol (the pure stuff, not the 70% you find in drug stores). Where I used to work they had gallons of the stuff for cleaning instruments and the like. Works just fine. Xylene is usually chosen for bubble chambers because it’s index of refraction closely matches that of the curved glass windows (making it a solid “block” as far as the light is concerned).The A-12 optical path is such that it doesn’t matter much, so isopropanol works just as well.
Paul Dolkas
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Jim Speedwell
Sent: Wednesday, October 04, 2017 1:49 PM
To: paul@dolkas.net
Subject: [NavList] Hardware store Xylene in A-12 bubble sextant?
I just bought an A-12 sextant with a dry bubble chamber, which I need to refill.
The manual calls for “chemically pure xylene”, I can find high purity xylene on Amazon, which seems to be good, but it’s expensive.
I know Hardware store Xylene contains impurities, what would be the harm of these impurities in a bubble chamber besides possibly leaving a residue?
And couldn’t you check for residue, by pouring the xyline into an open container and letting it to evaporate and then see if it left a film?
Thanks.
