Content deleted Content added
expand BTDR |
syntax |
||
Line 302:
The front dial has two concentric circular scales. The inner scale marks the Greek signs of the zodiac, with division in degrees. The outer scale, which is a movable ring that sits flush with the surface and runs in a channel, is marked off with what appear to be days and has a series of corresponding holes beneath the ring in the channel.
Since the discovery of the mechanism, this outer ring has been presumed to represent the 365 day Egyptian calendar, but recent research challenged this presumption and provided evidence it is most likely divided into 354 intervals.<ref name=budiselic>{{cite report |author1=Budiselic |display-authors=et al |date=December 2020 |title=Antikythera mechanism: Evidence of a lunar calendar |place=Newark, UK |publisher=British Horological Institute |website=BHI.Co.UK |url=https://bhi.co.uk/wp-content/uploads/2020/12/BHI-Antikythera-Mechanism-Evidence-of-a-Lunar-Calendar.pdf |access-date=12 December 2020 |archive-date=13 December 2020 |archive-url=https://web.archive.org/web/20201213144005/https://bhi.co.uk/wp-content/uploads/2020/12/BHI-Antikythera-Mechanism-Evidence-of-a-Lunar-Calendar.pdf |url-status=live }}</ref> Since this initial discovery, two research teams, using different methods, independently calculated the interval count. Woan and Bayley calculate 354–355 intervals using two different methods, confirming with higher accuracy the Budiselic et al. findings and noting that "365 holes is not plausible".<ref>{{cite arXiv |date=February 2024 |title= An improved calendar ring hole-count for the Antikythera mechanism |eprint=2403.00040 |last1= Woan |first1= Graham |last2= Bayley |first2= Joseph |class= physics.hist-ph }}</ref> Malin and Dickens' best estimate is 352.3±1.5 and they conclude that the number of holes, N, "has to be integral and the SE ([[standard error]]) of 1.5 indicates that there is less than a 5% probability that N is not one of the six values in the range 350 to 355. The chances of N being as high as 365 are less than 1 in 10,000. While other contenders cannot be ruled out, of the two values that have been proposed for N on astronomical grounds, that of Budiselic et al. (354) is by far the more likely."<ref name=budiselic /><ref>{{cite report |author1= Malin and Dickens |date=April 2024 |title=How Many Days in an Egyptian Year? Evidence from the Antikythera Mechanism |page= 144 |place=Newark, UK |publisher=British Horological Institute |website=BHI.Co.UK |url=https://bhi.co.uk/wp-
If one subscribes to the 365 day presumption, it is recognized the mechanism predates the [[Julian calendar]] reform, but the [[Sothic cycle|Sothic]] and [[Callippus|Callippic]] cycles had already pointed to a {{sfrac|365|1|4}} day solar year, as seen in [[Ptolemy III Euergetes|Ptolemy III]]'s attempted calendar reform of 238 BC. The dials are not believed to reflect his proposed leap day ([[Epag.]] 6), but the outer calendar dial may be moved against the inner dial to compensate for the effect of the extra quarter-day in the solar year by turning the scale backward one day every four years.
| |||