NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How does the AstraIIIb split mirror work?
From: Doug Royer
Date: 2004 Apr 22, 17:40 -0700
From: Doug Royer
Date: 2004 Apr 22, 17:40 -0700
Subject: How does the AstraIIIb split mirror work? Jim, As stated before I believe you only have to get used to useing it. On a more practical matter concerning your Astra's or any sextant's mirrors(or scope optics)note the following as you're a sea going man useing one.This nugget was is passed on to you from experiance. Coat your mirrors!Both of them.Coat your scope's lens also. Do as much as you can to protect the surfaces of the glass from spray etc. In the states there are a number of products to do this.The one I've used is known as "Rain-X".It leaves a coating on the surface that repels or reduces spray clinging to the glass.If the spray dries(you forgot to wipe clean after sights)it comes off the surface easily.If by mistake the sextant is stored with out cleaning it will retard damage to the glass surface.There is no harm done useing this to front or back silvered Index mirrors.Coat both the front and back surfaces of the horizon mirror. It in no way reduces the quality of the mirrors or scopes. You may already know all this,so if you do disreguard.