"චන්ද්‍ර සූර්ය දින දසුන්" හි සංශෝධන අතර වෙනස්කම්

{{දින දසුන්}}A '''චන්ද්‍ර සූර්ය දින දසුන''' යනු [[calendar]] in many [[culture]]s whose date indicates both the [[චන්ද්‍ර කලා]] and the time of the solar [[year]]. If the solar year is defined as a [[tropical year]] then a lunisolar calendar will give an indication of the [[season]]; if it is taken as a [[sidereal year]] then the calendar will predict the [[constellation]] near which the [[full moon]] may occur. Usually there is an additional requirement that the year have a whole number of months, in which case most years have 12 months but every second or third year has 13 months.

 

The [[Hebrew calendar|Hebrew]], [[Buddhist calendar|Buddhist]], [[Hindu calendar|Hindu lunisolar]], [[Tibetan calendar]]s, [[Chinese calendar]] (used alone until [[1912]] and then used along with the [[Gregorian calendar]]) and [[Korean calendar]] (used alone until 1894 and since used along with the [[Gregorian calendar]]) are all lunisolar, as was the [[Japanese calendar]] until [[1873]], the Hawaiian calendar, the [[Islamic calendar#Pre-Islamic calendar|pre-Islamic calendar]], the republican [[Roman calendar]] until [[45 BC]] (in fact earlier, because the synchronization to the moon was lost as well as the synchronization to the sun), the first century Gaulish [[Coligny calendar]], the [[Orthodoxwiki:Byzantine Creation Era|Byzantine Calendar]], and the [[second millennium BC]] [[Babylonian calendar]]. The Chinese, Coligny and

Hebrew<ref>The modern Hebrew calendar, since it is based on rules rather than observations, does not exactly track the tropical year, and in fact the average Hebrew year of ~365.2468 days is intermediate between the tropical year (~365.2422 days) and the sidereal year (~365.2564 days)

The 19-year cycle (235 synodic months, including 7 embolismic months) is the classic [[Metonic cycle]], which is used in most arithmetical lunisolar calendars. It is a combination of the 8- and 11-year period, and whenever the error of the 19-year approximation has built up to a full day, a cycle can be truncated to 8 or 11 years, after which 19-year cycles can start anew. [[Meton]]'s cycle had an integer number of days, although ''Metonic cycle'' often means its use without an integer number of days. It was adapted to a mean year of 365.25 days by means of the 4×19 year [[Callipic cycle]] (used in the Easter calculations of the Julian calendar).

 

 

The next approximation (arising from continued fractions) after the Metonic cycle (such as a 334-year cycle) is very sensitive to the values one adopts for the lunation (synodic month) and the year, especially the year. There are different possible definitions of the year so other approximations may be more accurate. For example (4366/353) is more accurate for a [[tropical year]] whereas (1979/160) is more accurate for a [[sidereal year]].

 

 

A rough idea of the frequency of the intercalary or leap month in all lunisolar calendars can be obtained by the following calculation, using approximate lengths of months and years in days:

 

A representative sequence of common and leap years is ccLccLcLccLccLccLcL, which is the classic nineteen-year [[Metonic cycle]]. The Buddhist and Hebrew calendars restrict the leap month to a single month of the year; the number of common months between leap months is, therefore, usually 36, but occasionally only 24 months. Because the Chinese and Hindu lunisolar calendars allow the leap month to occur after or before (respectively) any month but use the true motion of the [[sun]], their leap months do not usually occur within a couple of months of [[perihelion]], when the apparent speed of the sun along the [[ecliptic]] is fastest (now about 3 January). This increases the usual number of common months between leap months to roughly 34 months when a doublet of common years occurs, while reducing the number to about 29 months when only a common singleton occurs.

 

{{reflist}}

 

 

* [http://www.hermetic.ch/cal_stud.htm Calendar studies] ''A general discussion of calendar systems including two examples of lunisolar calendars.''

{{Time measurement and standards}}

{{Chronology}}

 

 

[[ca:Any embolismal]]

[[de:Lunisolarkalender]]

[[en:Lunisolar calendar]]

[[es:Calendario lunisolar]]

[[fi:Kuu-aurinkokalenteri]]