NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Universal astrolabe for finding bearing
From: Trammell H
Date: 2026 Jan 5, 07:57 -0800
From: Trammell H
Date: 2026 Jan 5, 07:57 -0800
I've written a quick demo of how to use a modern version of the universal astrolabe's stereographic projection to compute bearing (and approximate height) given Latitude, Declination and LHA: https://trmm.net/astrolabe/
I find the results are within a degree of Pub249 when using it on the slide rule, and a few degrees if I try the plastic sheet overlay method. It is definitely faster than the Bygrave or any hand calculation methods, and I find the circular slide rule is even faster than consulting the sight reduction tables. Plus you can use the bearing directly and don't have to perform any addtion or subtraction on the result for AM/PM, Same/Contrary Name, or different hemispheres.
File:
File:
