Search

Recovered in 1901, from a first-century BC shipwreck, the Antikythera Mechanism is considered to be the oldest extant complex geared device. It was constructed in ~150 BCE and was essentially an analog computer, an astronomical and calendrical device, designed to predict astronomical phenomena, such as lunar and solar eclipses, to maintain calendar accuracy and to predict the dates of Panhellenic Games. The device was operated manually by a user, setting a date in a dial. All necessary calculations were made using a set of gears (at least 39), while the results were displayed on several scientific scales. The Mechanism’s miniature size, the elaborate gear trains, the use of eccentrical gears and the employment of a pin–and–slot gear system to calculate the anomalous orbit of the Moon, demonstrate that the Greek mechanicians of the Hellenistic period had become far more skillful in designing geared devices than the surviving written sources imply. Geared devices matching the complexity of the Antikythera Mechanism would not appear again in Europe until the mechanical clocks of the thirteenth century. The aim of this paper is to present this ancient elaborate device in the most comprehensible way. [ABSTRACT FROM AUTHOR]

The Antikythera Mechanism is the oldest extant complex geared device, an amazing analogue computer. It was built approximately 2150 years ago. The device was operated manually by a user, setting a date in a dial. All necessary calculations were made using a set of gears (at least 39), while the results were displayed on several scientific scales. The Mechanism was used to calculate astronomical phenomena, such as solar and lunar eclipses. After an extensive description of the Mechanism, the main objective of the following paragraphs is to demonstrate the accuracy of its predictions.

The Antikythera Mechanism is the oldest extant complex geared device, an amazing analogue computer. It was built approximately 2150 years ago. The device was operated manually by a user, setting a date in a dial. All necessary calculations were made using a set of gears (at least 39), while the results were displayed on several scientific scales. The Mechanism was used to calculate astronomical phenomena, such as solar and lunar eclipses. After an extensive description of the Mechanism, the main objective of the following paragraphs is to demonstrate the accuracy of its predictions. [ABSTRACT FROM AUTHOR]

The article offers information on the originations of coordinated universal time (UTC) calendar. Topics discussed include the 24 hour day, the consolidation of the calendar systems of Egyptians and Greeks, and the Roman calendars. Also mentioned are the calendar of Roman General Julius Caesar, Gregorian calendar, and the origins of the seven day week.

Antikythera mechanism, dateable around to the first century BC, is the oldest known geared mechanism treated as an astronomical computer through the decoding of modern technology. In accordance with the decoded exterior dials and their functions, the interior mechanism was confirmed to consist of five corresponding subsystems. However, some unexplained problems still exist among these subsystems, such as the lunar subsystem, in which the visible pentagonal mark is positioned on the centre of a gear, demonstrating the lunar anomaly motion. From the viewpoint of mechanical design, this strange evidence implies the existence of a shaft with a complex structure, i.e. the coaxial gears with different rates. Also, it affects strongly the identifications of links and even the positions of gears. In order to provide other possible concepts to clarify this problem, this study synthesizes all feasible reconstruction designs through a systematic procedure. Through the study of historical literature, astronomical theories and existing designs, design constraints which are indispensible for the assignments of links and joints are concluded. Then, according to the concepts of generalization and specialization of mechanism, 13 feasible designs which are consistent with the theories and techniques of the subject’s time period, including the one by Freeth et al. are synthesized. Once new discoveries about the unexplained problem appear in the future, these feasible designs can be the corresponding answer. [ABSTRACT FROM AUTHOR]

There is a long-standing consensus of historians that Cambyses conquered Egypt in 525 BCE. This seemed very convenient as long as the reign of Amasis was supposed to have begun in 569 and to have lasted for 44 years. However, a lunar date shows that his accession has to be dated one year earlier. Up to now, the normal process was to ascribe to him an (unattested) 45th year in order to keep the following dates in their places. A study of the Egyptian sources shows that there is strong evidence against such a 45th year and that, given the maximum length of the reign of Psammetichus III, the Persian conquest has to be set in 526 BCE. Relevant texts and the question of dating praxis in Egypt under Cambyses are discussed. Also, a new translation of the decree of Dareios concerning the codification of the laws of Egypt is given, including several new readings. [ABSTRACT FROM AUTHOR]

Egyptian dates are widely used for fixing the chronologies of surrounding countries in the Ancient Near East. But the astronomical basis of Egyptian chronology is shakier than generally assumed. The moon dates of the Middle and New Kingdom are here re-examined with the help of experiences gained from Babylonian astronomical observations. The astronomical basis of the chronology of the New Kingdom is at best ambiguous. The conventional date of Thutmose III's year 1 in 1479 BC agrees with the raw moon dates, but it has been argued by several Egyptologists that those dates should be amended by one day, and then the unique match is 1504 BC. The widely accepted identification of a moon date in year 52 of Ramesses II, which leads to an accession of Ramesses II in 1279 BC, is by no means certain. In my opinion that accession year remains nothing more than one of several possibilities. If one opts for a shortened Horemhab reign, dating Ramesses II to 1290 BC gives a better compromise chronology. But the most convincing astronomical chronology is a long one: Ramesses II in 1315 BC, Thutmose III in 1504 BC. It is favored by Amarna-Hittite synchronisms and a solar eclipse in the time of Muršili II. The main counter-argument is that this chronology is at least 10-15 years higher than what one calculates from the Assyrian King List and the Kassite synchronisms. For the Middle Kingdom on the other hand, among the disputed dates of Sesostris III and Amenemhet III one combination turns out to be reasonably secure: Sesostris III's year 1 in 1873/72 BC and Amenemhet III's 30 years later. [ABSTRACT FROM AUTHOR]

The design of this paper is to consolidate a comprehensive model pertaining to the evolution of Egyptian calendars over three millennia of Pharaonic history, as an extension of this writer's earlier work on calendars. This model is a variation on the model advanced by Ludwig Borchardt and Richard Parker. While hardly immune from criticism, the Borchardt-Parker model has been prevalent in the second half of the twentieth century. According to this model, there were three calendars in ancient Egypt, two lunar and one non-lunar called civil. According to the variant model, there are only two calendars at any one time, the dominant civil calendar and a marginal lunar calendar of religious purport and of incomplete articulation. After the creation of the two calendars in prehistory and early history, only one truly significant event took place in all of Egyptian calendar history, around the fourteenth century B.C.E. Before the event, the lunar year began around the rising of Sirius in July. After the event, it began around the first new moon following civil New Year's Day. Owing to the backward wandering of the civil year, civil new year came to coincide with the rising of Sirius in the later fourteenth century B.C.E. The lunar calendar was unhooked from the rising, as it were, and attached and subordinated to the civil calendar. A double calendar, spiraling forward in time like a double helix, was the result. If the earlier and later beginnings of the lunar year are counted as two different calendars, there were three calendars, one civil and two lunar. However, it seems preferable to count just one lunar calendar, one that changed in regard to just one feature, its year's beginning. [ABSTRACT FROM AUTHOR]

This article presents an experiment in time series analysis, specifically the Rayleigh Test, applied to the ancient Egyptian calendars of lucky and unlucky days recorded in papyri P. Cairo 86637, P. BM 10474 and P. Sallier IV. The Rayleigh Test is used to determine whether the lucky and unlucky days are distributed randomly within the year, or whether they exhibit periodicity. The results of the analysis show beyond doubt that some of the lucky days were distributed according to a lunar calendar. The cycles of the moon thus played an important role in the religious thinking of the Egyptians. Other periods found using the Rayleigh Test are connected to the civil calendar, the mythological symbolism of the twelfth hour of the day and possibly the period of variation of the star Algol. [ABSTRACT FROM AUTHOR]

The Ebers calendar exhibits one sole instance of. This hieroglyph accompanies the name wp rnpt, presumably as a determinative, whereas the 11 other names in the same column conspicuously lack it. It is proposed that marks wp rnpt as the name of a lunar day whereas the 11 other names are the names of lunar months. This contrast between day and month is placed in the context of a comprehensive analysis of the entire Ebers calendar and of the original lunar calendar and its organic relation with the dominant civil calendar that the Ebers calendar is believed to portray. [ABSTRACT FROM AUTHOR]

The Almagest of Ptolemy (mid-second century ad) contains eleven dated reports of observations of the positions of planets made during the third century bc in Babylon and Hellenistic Egypt. The present paper investigates the character, purpose, and conventions of the observational programmes from which these reports derive, the channels of their transmission to Ptolemy's time, and the fidelity of Ptolemy's presentation of them. Like the Babylonian observational programme, about which we have considerable knowledge through cuneiform documents, the Greco-Egyptian ones were not directed towards the deduction of mathematical models of celestial motion but appear to have investigated patterns, correlations, and periodicities of phenomena. Ptolemy's immediate sources most likely were not the original series of observational records, but treatises by various astronomers of the intervening four centuries, including Hipparchus. While Ptolemy does not appear to have tampered with the wording of the reports, he faced difficulties and uncertainties in interpreting them; critically, he lacked sufficiently detailed information about the ancient calendars to be able to convert the reported dates accurately into his own chronological framework based on the Egyptian calendar. [ABSTRACT FROM AUTHOR]

Discusses the epagomenal days in ancient Egypt. Description of the calendrical setup of the transitional five days of the Egyptian Civil Year.

The article discusses historical aspects of calendars and almanacs. The author discusses how the phases of the moon, the change of seasons and astronomical observations inspired the creation of calendars as a way to to mark time and assist agriculture by identifying growing seasons. The Great Pyramids of Egypt were utilized to devise an Egyptian calendar that accurately measured the length of a year and divided it into months. The creation of Greek and Roman calendars, including those instituted by Roman emperors Numa Pompilius and Julius Caesar, is noted. Almanacs note astronomical phenomenon and other important statistics and climatic events that occur during a year. Almanacs were among the first publications created using the Gutenberg printing press.

The article discusses the astronomer Johannes Kepler, and the 364-day calendar discovered in the Dead Sea Scrolls. It notes that Kepler has shown an interest in historical chronology. He expresses his perspectives concerning the Gregorian reform of the calendar which has been the main topic of religious disputations between Catholics and Protestants. The debate also deals about the origin or the history of solar calendar. Meanwhile, Kepler believed that the Jewish calendar is the same as the 365 days depicted in the old Egyptian calendar.

The article discusses different types of calenders used before the time of Romans including Egyptian calender and lunar-based calendars.