NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Joshua Carty
Date: 2026 Mar 27, 06:46 -0700
Hello, Paul...
I have a Davis Mk 15 plastic sextant with a similar issue. I have since heard that there was production for a couple of years that had shades that were too weak, definitely inferior. Have you tried contacting Davis Instruments to see if they have any replacement offers? It seems to me that they should do this. As for me..... I have not tried reaching out to them.
The Davis is no longer my principal sextant, though I use it for Moon sights, planet sights, and horizontal angles but I'm no expert... Just playing around!
I assume that two aspects of light through a sextant scope should be considered when it comes to eye safety. Basic light intensity, plain "brightness", is not good for the eye all by itself. But I think our normal reflex to "flinch" and look away handles that. The other side is UV light. From what I understand, normal plastic shades should block UV. Does anyone know how to test that? How can I detect UV transmission through an optical system?
Josh
