NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Stacked-mirror sextant
From: Peter Monta
Date: 2018 Jun 1, 16:16 -0700
Interesting that the individual Bris elements are distributed over the entrance pupil of the lens, then the optical train superimposes everything once the image gets to the focal plane. There might be space for four Bris elements in a quad if you need even more Suns.
From: Peter Monta
Date: 2018 Jun 1, 16:16 -0700
Hi Greg,
I wonder if prisms could be used rather than mirrors.
Could be. Prisms are, if anything, even more robust, since the reflective surfaces are protected. Do you mean constant-deviation prisms like pentaprisms? They could prehaps be made very thin and then stacked.
My current prototype is much less ambitious and sticks with the standard Bris x2 on a 58mm uv camera filter and cut microscope slides 22mm x 25mm that are shimmed by pencil leads 0.7mm and 2mm. The resulting images (5,6,7,8) on each Bris do not need shading. Hs of 15 ,20 25 30...45,50,55 are formed for a useful set.
Cheers,
Peter
