A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Wayne Hilliard
Date: 2016 Dec 6, 12:34 -0800
According to general astronomical knowledge there are 3 options for safe viewing of the sun with optics. Projection onto a screen, metallized glass filter or metallized mylar film in a frame. For naked eye viewing of the sun with #14 welders glass. The po!arizer shades on my mark 2 sextant makes more sense to me then the colored plastic shades on the Davis plastic sextant I have. I have judged the thickness on vacuum deposited aluminum onto telescope optics by holding up and viewing the sun through it, If you see a dim blueish disk then you have about 100 nanometers of deposit. No idea on the testing of shades.