Daniel McCarthy

An evaluation of astronomical observations in the Irish annals

Abstract The astronomical entries scattered through the Irish annals have been examined in a serious astronomical context by R. R. Newton as part of his research into the accelerations of the earth and moon, and by D. Schove and A. Fletcher, as part of the Spectrum of Time project. They have never, however, been fully collated and examined as a whole as this paper undertakes to do. What emerges is a body of records from 442 to 1133 documenting eclipses, comets, aurorae, volcanic dust clouds and possibly a supernova; from 664 to 1133 all of these records are of observations made in or near Ireland, and most of them are accurate in their chronological and descriptive details. Analysis of the details of these records implies that, at least from the seventh to the eleventh centuries, careful and sustained observation and recording of astronomical phenomena were conducted in some Irish monasteries and it is clear that the underlying motive was religious and specifically eschatological, i.e. to detect the first signs of the end of time as prognosticated in the Book of Revelation. Critical examination of this data allows us to throw new light on the circumstances of the Synod of Whitby in 664, to identify the date of the eruption of the volcano Eldgja in Iceland as the springtime of 939 and to identify a possible Western observation of the supernova of 1054.

The lunar and Paschal tables of De ratione paschali attributed to Anatolius of Laodicea

Summary of conclusionsThe seven MS lunar and Paschal tables of De ratione paschali fall into two distinct groups which we have classified as Sirmond-type and Padua-type respectively, and from these we have restored the tables of their archetype. The Sirmond-type tables preserve a unique lunar year, which we term the Anatolian lunar year, and they first emerge in the context of a larger computus which was assembled in southern Ireland c. 658, a copy of which Wilfrid had evidently obtained by the time of the Synod of Whitby. The weight of circumstantial evidence supports the hypothesis that it was he who then instigated the corruption of both the tables and the patristic authorities of De ratione paschali, a copy of which subsequently passed to Bede and thence to the Sirmond group of MSS. The Padua-type tables on the other hand are represented only by the Padua MS, and they appear to have originated from within Insular circles on the Continent. These too were crudely corrupted, first by changing their lunar year from Anatolian to Roman and moving their ferial data from January to December and changing some Paschal data, and then secondly by collation with Sirmond-type tables. In the case of both types the objective was clearly to weaken the relationship between the lunar and Paschal tables and to try and obscure the Paschal principles that they preserve and thereby undermine the position of those followers of the Insular latercus who relied on the authority of De ratione paschali for their Pasch. These conclusions naturally give a rather different colour to the events of Whitby from that given by Bede, who places them completely in a theological context. However in material terms what was really at stake at Whitby was the transfer of the patronage of the entire kingdom of Northumbria from the Celtic to the Roman church. Here then was sufficient motivation to justify the most ruthless of expedients.