Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions

Balázs Bernáth, Miklós Blahó, Ádám Egri, András Barta, György Kriska, Gábor Horváth

Research output: Article

12 Citations (Scopus)

Abstract

It is widely accepted that Vikings used sun-compasses to derive true directions from the cast shadow of a gnomon. It has been hypothesized that when a cast shadow was not formed, Viking navigators relied on crude skylight polarimetry with the aid of dichroic or birefringent crystals, called "sunstones." We demonstrate here that a simple tool, that we call "shadow-stick," could have allowed orientation by a sun-compass with satisfying accuracy when shadows were not formed, but the sun position could have reliably been estimated. In field tests, we performed orientation trials with a set composed of a sun-compass, two calcite sunstones, and a shadow-stick. We show here that such a set could have been an effective orientation tool for Vikings only when clear, blue patches of the sky were visible.

Original languageEnglish
Pages (from-to)6185-6194
Number of pages10
JournalApplied Optics
Volume52
Issue number25
DOIs
Publication statusPublished - szept. 1 2013

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering

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