Lunisolar calendar in the context of "Lunar calendars"

⭐ In the context of lunar calendars, what is a key characteristic resulting from the discrepancy between the length of a lunar year and a solar year?

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⭐ Core Definition: Lunisolar calendar

A lunisolar calendar is a calendar in many cultures, that combines monthly lunar cycles with the solar year. As with all calendars which divide the year into months, there is an additional requirement that the year have a whole number of months (Moon cycles). The majority of years have twelve months but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leap month.

In contrast to purely lunar calendars such as the Islamic calendar, lunisolar calendars have additional intercalation rules that reset them periodically into a rough agreement with the solar year and thus with the seasons.

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👉 Lunisolar calendar in the context of Lunar calendars

A lunar calendar is a calendar based on the monthly cycles of the Moon's phases (synodic months, lunations), in contrast to solar calendars, whose annual cycles are based on the solar year, and lunisolar calendars, whose lunar months are brought into alignment with the solar year through some process of intercalation – such as by insertion of a leap month. The most widely observed lunar calendar is the Islamic calendar. The details of when months begin vary from calendar to calendar, with some using new, full, or crescent moons and others employing detailed calculations.

Since each lunation is approximately 29+12 days, it is common for the months of a lunar calendar to alternate between 29 and 30 days. Since the period of 12 such lunations, a lunar year, is 354 days, 8 hours, 48 minutes, 34 seconds (354.36707 days), lunar calendars are 11 to 12 days shorter than the solar year. In lunar calendars, which do not make use of lunisolar calendars' intercalation, the lunar months cycle through all the seasons of a solar year over the course of a 33–34 lunar-year cycle (see, e.g., list of Islamic years).

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Lunisolar calendar in the context of Attic calendar

The Attic calendar or Athenian calendar is the lunisolar calendar beginning in midsummer with the lunar month of Hekatombaion, in use in ancient Attica, the ancestral territory of the Athenian polis. It is sometimes called the Greek calendar because of Athens's cultural importance, but it is only one of many ancient Greek calendars.

Although relatively abundant, the evidence for the Attic calendar is still patchy and often contested. As it was well known in Athens and of little use outside Attica, no contemporary source set out to describe the system as a whole. Further, even during the well-sourced 5th and 4th centuries BC, the calendar underwent changes, not all perfectly understood. As such, any account given of it must be a tentative reconstruction.

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Lunisolar calendar in the context of Chinese calendar

The Chinese calendar is a lunisolar calendar created by or commonly used by the Chinese people. While this description is generally accurate, it does not provide a definitive or complete answer. A total of 102 calendars have been officially recorded in classical historical texts. In addition, many more calendars were created privately, with others being built by people who adapted Chinese cultural practices, such as the Koreans, Japanese, Vietnamese, and many others, over the course of a long history.

A Chinese calendar consists of twelve months, each aligned with the phases of the moon, along with an intercalary month inserted as needed to keep the calendar in sync with the seasons. It also features twenty-four solar terms, which track the position of the sun and are closely related to climate patterns. Among these, the winter solstice is the most significant reference point and must occur in the eleventh month of the year. Each month contains either twenty-nine or thirty days. The sexagenary cycle for each day runs continuously over thousands of years and serves as a determining factor to pinpoint a specific day amidst the many variations in the calendar. In addition, there are many other cycles attached to the calendar that determine the appropriateness of particular days, guiding decisions on what is considered auspicious or inauspicious for different types of activities.

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Lunisolar calendar in the context of Babylonian calendar

The Babylonian calendar was a lunisolar calendar used in Mesopotamia from around the 2nd millennium BC until the Seleucid Era (294 BC), and it was specifically used in Babylon from the Old Babylonian Period (1780s BC) until the Seleucid Era.

In the Seleucid Era it was reformed as "Greek time", Anno Graecorum was introduced and used in the Middle East and Egypt until the middle of the first millennium when the First Council of Nicaea AD 325 defined the Church year based on the Roman early Julian calendar. As Anno Graecorum formed the basis for time references in the Bible and spread westward, it rather increased the Babylonian calendars importance. The Babylonian calendar is also partly reflected in calendars in South and East Asia and the Islamic calendar as well as Iranian calendars. The Julian calendar inherited the definitions of the 12 month system, week, hour etc. from the Babylonian calendar and the current Jewish calendar can be seen as a slightly modified Babylonian calendar that still exists today and is practised, but with Anno Mundi Livryat haOlam year calculation since the creation of the world. Today's global time system UTC (Gregorian calendar) therefore has its main structure inherited from the Babylonian calendar.

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Lunisolar calendar in the context of Meton of Athens

Meton of Athens (Greek: Μέτων ὁ Ἀθηναῖος; gen.: Μέτωνος) was a Greek mathematician, astronomer, geometer, and engineer who lived in Athens in the 5th century BC. He is best known for calculations involving the eponymous 19-year Metonic cycle, which he introduced in 432 BC into the lunisolar Attic calendar. Euphronios says that Colonus was Meton's deme.

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Lunisolar calendar in the context of Julian calendar

The Julian calendar is a solar calendar of 365 days in every year with an additional leap day every fourth year (without exception). The Julian calendar is still used as a religious calendar in parts of the Eastern Orthodox Church and in parts of Oriental Orthodoxy as well as by the Amazigh people (also known as the Berbers). For a quick calculation, between 1901 and 2099 the much more common Gregorian date equals the Julian date plus 13 days.

The Julian calendar was proposed in 46 BC by (and takes its name from) Julius Caesar, as a reform of the earlier Roman calendar, which was largely a lunisolar one. It took effect on 1 January 45 BC, by his edict. Caesar's calendar became the predominant calendar in the Roman Empire and subsequently most of the Western world for more than 1,600 years, until 1582 when Pope Gregory XIII promulgated a revised calendar. Ancient Romans typically designated years by the names of ruling consuls; the Anno Domini system of numbering years was not devised until 525, and became widespread in Europe in the eighth century.

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Lunisolar calendar in the context of Embolismic month

Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of days or months.

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