| Tartalom: |
http://real.mtak.hu/9248/ |
| Archívum: |
REAL |
| Gyűjtemény: |
Status = Published
Subject = D History General and Old World / történelem: DL Northern Europe, Scandinavia / Észak-Európa, Skandinávia
Subject = Q Science / természettudomány: QC Physics / fizika: QC02 Optics / fénytan
Type = Article
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| Cím: |
Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions.
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| Létrehozó: |
Bernáth, B.
Blahó, M.
Egri, Ádám
Barta, A.
Kriska, György
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| Dátum: |
2013
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| Téma: |
DL Northern Europe, Scandinavia / Észak-Európa, Skandinávia
QC02 Optics / fénytan
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| Tartalmi leírás: |
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.
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| Típus: |
Article
PeerReviewed
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| Formátum: |
text
text
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| Azonosító: |
Bernáth, B. and Blahó, M. and Egri, Ádám and Barta, A. and Kriska, György (2013) Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions. APPLIED OPTICS (2004-), 52 (25). pp. 6185-6194. ISSN 1559-128X
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