A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Modris Fersters
Date: 2021 Mar 17, 12:19 -0700
According to my own experience normal glass does not has both surfaces absolutely paralel each other. When I want to achieve maximum accuracy using artfical horizon I use home made wind shade. The frame is made of carton (but it may be made of all available materials) and the cover is made from ordinary food film. This membran is very, very thin and therefore the rays passing throug the film are not disturbed. Of course, the film should be streched and then fixed in place by adhesive tape. I made my shade not in shape of prism (as it can be seen in your attached pitcure) , but insted of it I used curved upper surface.