Interesting Facts about Calendars

A calendar is a system of organizing time units for reckoning time over extended periods. It is a system of organizing days. A calendar can also mean a list of planned events, such as a court calendar or a partly or wholly chronological list of documents, such as a calendar of wills. Some calendars replicate astronomical processes according to fixed rules, others are based on abstract, perpetually repeating cycles of no astronomical significance. Astronomical observations regulate some calendars, carefully and redundantly enumerate every unit, and some contain ambiguities and discontinuities. This lunar calendar occasionally adds one intercalary month to remain synchronized with the solar year over the long term.

Interesting Facts about Calendars



LUNAR CALENDAR : A lunar calendar is one in which days are numbered within each lunar phase cycle. Because the length of the lunar month is not an even fraction of the size of the tropical year, a purely lunar calendar quickly drifts against the seasons, which do not vary much near the equator. It does, however, stay constant concerning other phenomena, notably tides. An example is an Islamic calendar.

SOLAR CALENDAR : Solar calendars are based on perceived seasonal changes synchronized to the apparent motion of the Sun, an example is a Persian calendar. A date for each solar day. A day may consist of the period between sunrise and sunset, with a following period of the night, or it may be a period between successive events such as two sunsets. The length of the interval between two such consecutive events may be allowed to vary slightly during the year.

COMBINED CALENDAR : Lunisolar calendars are based on a combination of both solar and lunar reckonings. The traditional calendar of China, the Hindu calendar in India and Nepal, and the Hebrew calendar are some examples. In this case, ordinary years consist of twelve months, but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leaps month. The lunisolar calendar is a lunar calendar that compensates by adding an extra month to realign the months with the seasons.



ASTRONOMICAL CALENDAR : The calendar year period contains 365 days or, in a leap year, 366 days. It is based on the Gregorian calendar, is divided into 12 calendar months, and is reckoned from January 1 to December 31. An astronomical calendar is based on ongoing observation.

THE HEBREW CALENDAR : In principle, the beginning of each month is determined by a tabular New Moon (molad) based on an adopted mean value of the lunation cycle. According to the Metonic process, months are intercalated to ensure that religious festivals occur in appropriate seasons.


  • They used the star Sirius closely to the true solar year, only 12 minutes shorter. However, specific difficulties arose because of the inherent incompatibility of lunar and solar years. To solve this problem, the Egyptians invented a schematized civil year of 365 days divided into three seasons, each consisting of four months of 30 days each.
  • Civil calendar was derived from the lunar calendar (using months) and the agricultural, or Nile, fluctuations (using seasons); it was no longer directly connected to either and thus was not controlled by them. The civil calendar served government and administration, while the lunar calendar regulated religious affairs and everyday life.



THE ROMAN CALENDAR : It was the seventh -eighth century when this calendar originated in the city of palaces, Rome, before the Christian Era. The year began in March and consisted of 10 months with 304 days and ended in December

THE JEWISH CALENDAR : The calendar term here is yereaḥ, which in Hebrew denotes both “moon” and “month.” The second Hebrew term for a month, ḥodesh, properly means the “newness” of the lunar crescent. Thus, the Hebrew months were lunar. In some passages, the Passover month is the lunation that coincides with the barley being in the ear. Thus, the Hebrew calendar is tied in with the course of the Sun, which determines the ripening of the grain. It is unknown how the lunar year of 354 days was adjusted to the solar year of 365 days. There is no reference to New Year’s Day in the Bible.

THE MUSLIM CALENDAR : The Muslim era began with the emigration of Muhammad, the Prophet of Islam, from Mecca to Medina. The second Caliph set the first day of the month of Muharram as the beginning of the year, which the holy Quran fixes. They are an example of a lunar calendar and consist of 12 lunar months. The months do not keep to the same seasons as the Sun because there are no intercalations of months. The months regress through all the seasons every 32 ½ years. Ramadan, the ninth month, is observed throughout the Muslim world as a month of fasting, and Muslims must see the moon and begin fast.




  • Indians solely adopt the Gregorian calendar to represent their ‘secularism. However, the Hindu religious life runs according to the typical traditional Hindu Calendar, based on lunar revolutions. Hindu Calendar is one of the most classical and oldest ones based on texts of 1000 BCE, and it is also based on 12 lunar months.
  • These constellations are called nakshatra. Based on the position of the sun, moon, constellation and planets, every event and festival is planned and executed. The seasons are changed based on uttarayana (Northern course ) and Dakshinayan (Southern course ). The day starts at dawn; the first six ghatikas are early morning, the second set of six midmornings, the third midday, the fourth afternoon, and the fifth evening. Night lasts through three units of time: six ghatikas after sundown, or early night; two of midnight; and four of dawn

THE CHINESE CALENDAR : Since the calendar is based on the Sun and Moon’s actual positions, the calendar’s accuracy depends on the accuracy of the astronomical theories and calculations. The traditional Chinese calendar is used to set traditional festivals and timing agricultural activities in the countryside. Chinese communities around the world also use the Chinese calendar.



THE JULIAN CALENDAR : The name suggests that Julian Caesar introduced it. It was a solar calendar with months of fixed lengths. An intercalary day was added to maintain synchrony between the calendar year and the tropical year every fourth year. It served as a standard for European civilization. This provides a simple chronological system for correlating other calendars and the basis for the Julian day numbers.

THE GREGORIAN CALENDAR : It regulates the ceremonial cycle of the Roman Catholic and Protestant churches. Its original purpose was ecclesiastical. Although various other calendars are in use today, they are restricted to particular religions or cultures.

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