Sothic Cycle - Problems and Criticisms

Problems and Criticisms

Determining the date of a heliacal rise of Sothis has been shown to be difficult, especially considering the need to know the exact latitude of the observation. Another problem is that because the Egyptian calendar loses one day every four years, a heliacal rise will take place on the same day for four years in a row, and any observation of that rise can date to any of those four years, making the observation not extremely precise.

A number of criticisms have been leveled against the reliability of dating by the Sothic cycle. Some are serious enough to be considered problematic (for example; 1. none of the astronomical observations have dates that mention the specific pharaoh in whose reign they were observed, forcing Egyptologists supply that information on the basis of a certain amount of informed speculation, 2. there is no information regarding the nature of the civil calendar throughout the course of Egyptian history, forcing Egyptologists to assume that it existed unchanged for thousands of years), other criticisms are not considered as problematic (for example; there is no extant mention of the Sothic cycle in ancient Egyptian writing, which may simply be a result of it either being so obvious to Egyptians that it didn't merit mention or to relevant texts being destroyed over time or still awaiting discovery). Some have recently claimed that the Theran eruption marks the beginning of the Eighteenth dynasty due to Theran ash and pumice discoveries in the ruins of Avaris in layers that mark the end of the Hyksos era. Because the evidence of dendrochronologists indicates the eruption took place in 1626 BC, this has been taken to indicate that dating by the Sothic cycle is off by 50–80 years at the outset of the 18th dynasty. Claims that the Thera eruption is the subject of the Tempest Stele of Ahmose I have been disputed by writers such as Peter James