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HALASTJÖRNUR, SÓLMYRKVAR, ELDGOS OG ÁREIÐANLEIKI ANNÁLA 99
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SUMMARY
COMETS, ECLIPSES, ERUPTIONS AND THE RELIABILITY
OF THE ICELANDIC CHRONICLES AD 1150-1400.
The historic reliability of the Icelandic medieval literature has often been a matter of
debate. The Sagas, formerly believed to be the holy truth, are now generally considered
to follow the rules of the fiction but the mediaeval chronicles and historical literature such
as Sturlunga Saga and The Episcopal Sagas have often been used and are still frequently
cited as firm historical documents. In the research of historical volcanism in Iceland these
sources have served to confirm an absolute time scale and the Icelandic tephrochronology
is based on the records of the chronicles from the first historical eruption of Hekla AD
1104 up to the 19. century.
The appearance of a comet on the celestial sphere is a global phenomenon whereas an
eruption most often is a very local event. If the Icelandic written scources are reliable in
the timing of comets, which can be tested by comparison with foreign chronicles and
astronomical catalogues, one should conclude that the timing of eruptions would be
equally reliable.
Here a comparison is made of cometary observations in the Icelandic medieval litera-
ture (mostly chronicles) and foreign chronicles during the period 1150-1400 AD in order
to get some indications of the reliability of the Icelandic sources. In this period the Ice-
landic literature mentions 11 individual comets. In eight cases they are in full agreement
with the best foreign sources and three times there is a one year displacement. When the
Icelandic sources mention a comet they are correct ± 1 year. Sources on eclipses of the
sun were also compared and they proved to be observed and dated by similar accuracy.