Modelling of Islamic Calendar System based on Moon Phase (original) (raw)

Are Islamic Legacy Calendars of the Lunar Type, Really? Measurement of the Deviation

JISC, 2024

Background and Purpose: This study aims to demonstrate that the so-called Islamic legacy calendars are of the Gregorian-like type far from corresponding to the properties of the synodic lunar month. This unexpected result provided the first stone from which the search for a coherent definition of legacy criterion has been undertaken in this work. Material and Methods: To this end, distributions of time lag (∆t 0), the time distance between the lunar conjunction (LC) and the first lunar day of the month, were processed and used to estimate the 1 st −Day rejection index (R I) for four computerized calendar paradigms used in Lausanne city, between1938 and 2038. Those estimates measured the deviations from the lunar synodic properties caused by the underlying hypotheses. In addition, new synoptic figures of the projected 2023/1444H Ramadan calendars in twelve pilot cities were computed to highlight the fundamental reason for mismatch along with specific assessment. Those figures also aimed to illustrate the competitive effects of four environmental parameters on final issues, namely: LC, latitude, time zone and season. Results: Several results were found: R I was ranging between 45% and 90% while the corresponding rejection thresholds were between 8h and 18h. The synoptic figures, while fully explaining the similarities and differences between the calendars in and between cities with all their respective 1 st −Day dates being summarized in "Confusion Tables", they also contributed to demonstrate that all the residual flaws of the Islamic calendars were caused by explicit and implicit assumptions of unfounded "day reference times" (DRT), as if the lunar context was assimilated to a Gregorian-like one. Conclusion: The results were finally analyzed within the framework of the "inclusive science approach" (ISA) and a new proposal was made in favor of a "single and universal" Islamic calendar legacy definition, which conforms on the one hand, to the properties of the lunar synodic month and on the other hand, to lunar Islamic requirements.

Arc-Light. Application to the Islamic Calendar

We show techniques for finding the arc-light, or angle between the centers of the Sun and the Moon. We describe the periodicity of the Moon's ecliptic latitude and its effect on the arc-light. We verify that the arc-light at the New Moon time has a periodicity of approximately 173.5 days. We define the topocentric New Moon, which occurs when there is a relative minimum of the topocentric arc-light.

Using Algorithm Jean Meuus and Solrad Simulation Application in Determining Early Months Qamariyah

Procedia - Social and Behavioral Sciences, 2012

In terms of determining the beginning of the month Qamariah required reasoning of astronomy, Science of this is one area of science that is recommended to be studied in order to determine it Muslim worship such as fasting, Eid-ul-Fitr, Hajj, and others-others. Practically Science of Falak is widely used to determine the direction of Qibla (Direction Muslim prayers) from a place far from the place where it can not directly see the Ka'bah (the reference point for determining the direction Muslims worship Shalaf). Science of Falak is also useful for determining the beginning of the month or the 1st of every month for Qamariyah (Years by or determined by the circulation of the month). A large difference in determining Qamariah beginning is often the case in Indonesia and a debate every year, for that to be expected with this research is to help Jean Meuus and Solrad algorithms in the form of simulator applications can help in the early months of Qomariah determine the support of Data Ephemeris Sun and moon obtained from several options algorithms accurately recognized by the astronomical community, early calculations using solar Ephemeris data method in accordance with the calculation in the Department of Religious Affairs in the State of Indonesia.

THE HIJIRI CALENDAR AND ITS CONFORMANCE WITH THE GREGORAIN CALENDAR BY MATHEMATICAL CALCULATIONS

Hijri Calendar and its Conformance to Gregorian Calendar by Mathematical Calculations , 2024

The objective of this research is to develop a mathematical procedure to construct a Hijri calendar that is consistent with the Gregorian calendar. Our hypothesis was derived from the Quran Chapter, Alkahf verse (25), which states "They remained in their cave for three hundred years, adding nine". We understand this verse to mean "every 300 solar years equivalent exactly to 309 lunar years". The starting point was to locate the number of days for each month of each Hijri year. We found that the distribution of number of days per month coincided in the two rounds of the 309 Hijri years. Accordingly, we prepared a list of number of days per month for 1545 Hijri years. Hence, we constructed Hijri calendar starting consecutively from 1 Muharram 1AH to any Hijri Date. We considered the Gregorian Date consistent with the first of Ramadan 1442AH as a relevant reference versus the historical reference of the migration of Prophet Mohammed ‫هللا‬ ‫صلى‬ ‫وسلم‬ ‫عليه‬ to Medina. Finally, we compared our results with previous official dates Therefore any Gregorian date corresponds to Hijri date could be known.

Study the variation of synodic month for the moon through 2000-2100

Iraqi Journal of Physics (IJP), 2019

In this research study the synodic month for the moon and theirrelationship with the mean anomaly for the moon orbit and date A.Dand for long periods of time (100 years), we was design a computerprogram that calculates the period of synodic months, and thecoordinates of the moon at the moment of the new moon with highaccuracy. During the 100 year, there are 1236 period of synodicmonths.We found that the when New Moon occurs near perigee (meananomaly = 0°), the length of the synodic month at a minimum.Similarly, when New Moon occurs near apogee (mean anomaly =180°), the length of the synodic month reaches a maximum. Theshortest synodic month on 2053 /1/ 16 and lasted (29.27436) days.The longest synodic month began on 2008 /11/ 27 and lasted(29.81442) days. The mean synodic month (29.53109) days. Wefound the relationship between synodic month with months. Theshortest synodic month are correlated with date (June and July) whenthe Earth is near aphelion. And the longest Synodic month ar...

Global Hijriyah Calendar As Challenges Fikih Astronomy

2018

Unification of hijri calendar occupies very important position because the calendar system adopted as symbol of civilization, particularly for Islamic civilization which no enter the era of 1.5 millennium and has not global calendar system. The hijri calendar system is lunar calendar based on the circulation of the moon around the earth. In astronomical science, the movement of the moon from new month to the next can be calculated carefully and accurately so that the demands of the predictable calendar system can be fulfilled. The discourse of the hijri calendar in the Islamic world is closely related to the use of method in determining the beginning of the lunar month. Todays, there are two methods used by Muslims in determining the beginning of the month, the method of Hisab and Rukyat. The method of hisab is predictable and its accordance with the calendar is also predictable, while the rukyat method is nonpredictable, bringing the correlation between two methods that challenge a...

A Unified Islamic Calendar Proposal for the World

2014

2 Abstract: To date, there is no single global Islamic calendar for the community. Over the years, the computation of the Islamic calendar has become a subject of much debate. In this paper, we propose a unified global Islamic calendar (UGIC) based in the concept of "expected visibility", International Dateline and a single calendar for the whole world. We used a new sightability criterion to determine young crescent visibility that is based on eye-detectable contrast between the crescent illumination and sky background. We propose an unconventional reference for calendar construction that is based on a line instead of a point. We embraced the International Date Line as day (and month) separator. A three-year calendar has been produced based on the above method for evaluation.

Semi-regular Islamic Arithmetic Calendar

We expose the techniques to find computational lunar calendars. We distinguish between regular and semi-regular calendars. We study the Islamic calendar proposed by Rashed, Moklof, and Hamza, and we use the chronological Julian day to do the conversion to other calendars.

The Islamic Lunar Calendar as a Civilizational Imperative

The Islamic Lunar Calendar as a Civilizational Imperative - The American Journal of Islamic Social Sciences Vol. 9, No.4, 1992

It is He Who made the sun a radiance, and the moon a light, and determined it by stations, that you might know the ‎number of the years and the reckoning (of time) . . . ( Qur’an 10:5).‎