A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ed Popko
Date: 2015 Aug 29, 13:28 -0700
I see navigation techniques and relationships in many places. We don’t have a monopoly!
For instance, there is strong evidence that the Vikings navigated on cloudy days by using sunstone, also called Iceland Spar. It’s a type of transparent calcite, that exhibits light-polarizing properties that can tell the direction of the sun within a few degrees in both cloudy and twilight conditions.
The Academy of Science paper in the reference given suggests the Dung Beetles are doing the same thing with light polarization.
The 1992 recovery of an Iceland Spar sunstone from the Elizabethan ship Alderney (1592) suggests that Iceland Spar and light polarization were regular navigation practice among the Vikings.