A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2016 Sep 21, 02:24 -0700
I'm experimenting with few bits of glass to build a DIY "Bris".
This article describes a tool with a set of reflections at 13°, 22°, 26°, 35°, 44°, 48°, 57° and 70°. Is this set optimal for real-life observations? If not - what agnle values should I aim for in my design?
I hope to use it (or - most probably - a pair of "Bris"s) somewhere between equator and 60°.
The other question: what size of the device is most comfortable?
Right now my pieces of glass are 25mm·15mm - similar to author's article. I tried them on a sunny day - it was painfull to use (despite the 9 DIN welding filter was used) because 15mm-narrow "bris" does not cover the eyeball enough. The bright light from the right and left part of the sky still blinds me. When I did my initial tests with the uncut filter (110mm·150mm) there was no such problem. I'd like to avoid using any rubber eyecups...
Please share your experience.