NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Index mirror type
From: Igor S.
Date: 2019 Mar 18, 14:48 -0700
From: Igor S.
Date: 2019 Mar 18, 14:48 -0700
Hello everyone,
I don't know if somebody have noticed that index mirror in different sextants are of different types namely either first or second surface mirrors. I've made some comparison photos (Tamaya vs. Freiberger sextants) from where it is clearly can be seen. As we see Tamaya has second while Freiberger (and also Russian sextants) firs surface mirrors.
https://en.wikipedia.org/wiki/First_surface_mirror
First surface mirror reflects a bit more light which is a slight advantage for star sights but it is more prone for scratches and is more expensive.
Any more advantages or disadvantages of either?
kind regards,
Igor
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