Related papers: The Mayan Long Count Calendar
The Mayan calendar is proposed to derive from an arithmetical model of naked-eye astronomy. The Palenque and Copan lunar equations, used during the Maya Classic period (200 to 900 AD) are solution of the model and the results are expressed…
Ancient mesoamerican cultures built a short ritual 260 day calendar and used it for daily routinary life. Using simple arithmetic calculations it is first shown that by forcing the introduction of the the fundamental number 13 to calculate…
We argue that there was a link between Indus Valley India and the Mayans of Central America which is brought out by astronomical references. The former used a Jovian calendar while the latter had perfected a calendar based on Venus. This…
The Mayan culture collected exquisite astronomical data for over a millennium. However, it failed to come up with the breakthrough ideas of modern astronomy because the data was analyzed within a mythological culture of astrology that…
The official Iranian calendar is a solar one that in both the length and the first day of its year is based not on convention, but on two natural (i.e. astronomical) factors: a) the moment of coincidence of the centre of the Sun and the…
The Ancient Egyptians wrote Calendars of Lucky and Unlucky Days that assigned astronomically influenced prognoses for each day of the year. The best preserved of these calendars is the Cairo Calendar (hereafter CC) dated to 1244--1163 B.C.…
Pre-Columbian Mesoamerica was a fertile crescent for the development of number systems. A form of vigesimal system seems to have been present from the first Olmec civilization onwards, to which succeeding peoples made contributions. We…
A perpetual calendar, a calendar designed to find out the day of the week for a given date, employs a rich arithmetical calculation using congruence. Zeller's congruence is a well-known algorithm to calculate the day of the week for any…
An ancient Egyptian Calendar of Lucky and Unlucky Days, the Cairo Calendar (CC), assigns luck with the period of 2.850 days. Previous astronomical, astrophysical and statistical analyses of CC support the idea that this was the period of…
The family of Tibetan lunisolar calendars operates on a shared arithmetic axiom (67 lunar months = 65 solar months) that provides a rigid structure but causes observable seasonal drift. This study deconstructs the calendar through a…
An explanation is provided for the Inca counting board described by Guaman Poma in 1615. Although the board could have been used in more than one way, we show that based on certain reasonable assumptions regarding non-uniform representation…
This article advances the hypothesis that the heightened eschatological sensitivity evident among the historians writing in the 5th century and its weaker echos in the time of Charlemagne were caused by the irregularities of the the…
This paper centers on the collection of accounts on solar eclipses from the era of the Aztecs in Mesoamerica, about 1300 to 1550 AD. We present a list of all eclipse events complying with the topological visibility from the capital…
We compute the mean interval between successive returns of the apparent geocentric solar longitude $\lambda$ to a fixed value $L \in \{0^\circ, 45^\circ, 90^\circ, \ldots, 315^\circ\}$, averaged over a multi-millennium window; this gives…
It is shown that each sequence giving the number of times a given day of the month falls on a certain day of the week for $400$ successive years of the Gregorian cycle can be composed of various pieces of various length of one of 4…
The traditional cultures of Aboriginal Australians include a significant astronomical component, perpetuated through oral tradition, ceremony, and art. This astronomical component includes a deep understanding of the motion of objects in…
This article provides information about the factors that necessitated the need to adjust the calendar during the time of Umar Khayyam, the method of choosing the beginning of the year, and the length of the months. It also attempts to…
Lunar occultation can be used to measure the proper motions of some of the long time scale microlensing events, $t_{e} \gsim 70$ days, now being detected toward the Galactic bulge. The long events are difficult to explain within the context…
We present a general description of the Iranian calendar and Nowruz, which starts at the precise instant when the Sun coincides with the vernal equinox. Although the paper aims at the basic astronomical elements of the calendar, historical…
This is a historian's view of how modern astronomy data can be used to discuss the shifting historical worldview of Late Antiquity. In this article an attemp is made to construct an approximate model of how the cycles of astronomical…