Types of Calendars
Types of Calendars
Calendars, as the time counting system, are based on periodical observations of natural cycles: days, months and years. The length of the day is determined by the time of Earth revolution around its axis, of the month by the time of Moon revolution around Earth, of the year by the time of Earth revolution around Sun. According to how the calendar motion is coordinated with the motions of the Moon and the Sun conditionally, calendars could be divided into the following types.
Lunar calendar.
Synodical month (period of time, when Moon phases are repeated) is the basis
of the lunar calendar. Synodical month period is a changeable quantity and its
medium size at present is 29.530588 days. In lunar calendars the beginning of
the calendar month coincides with the New Moon or with the first Moon's crescent
appearance in the sky after New Moon, and the year length does not correspond to
the tropical year length, which leads to the situation, that one and the same
month in different years falls on different seasons. The
lunar Islamic (Hegira) calendar is an example of
the lunar calendar.
Solar calendar.
The tropical year — the period between two consecutive Vernal
equinoxes, the medium size of which is 365.242 days, is the basis of the solar
calendar. The year in the solar calendar is divided into months, the length and
beginning of which are not coordinated with the Moon movement, but which every
year fall on the same seasons. Julian,
Gregorian and
National calendar of India are examples of the solar calendar.
Lunisolar calendar.
Lunisolar calendar is arranged in such a way, that its months are
coordinated with the synodical month as in the lunar calendar, and the medium
length of the year is coordinated with the tropical year as in the solar
calendar.
Hebrew calendar could be an example.
Calendars Initials
Generally accepted abbreviations of certain eras:
| B.C.E. | Before the Common Era |
| C.E. | Common Era |
| B.C. (Before Christ) | Before Jesus Christ�s birth |
| A.D. (Anno Domini) | After Jesus Christ�s birth |
| A.H. (Anno Hegira) | After the Hegira (Mohammed's flight to Medina) |
| A.M. (Anno Mundi) | After Creation of the World |
| S.E. | Saka Era |
| A.M. (Anno Martyrum) | From Martyrs Era (Christians persecutor Rome Emperor Diocletian accession to power) |
| E.E. (Ethiopic Era) | From Ethiopian Era |
| A.P. (Anno Persarum) | From Persian Era |
The abbreviation C.E. is a standard way of denoting dates in scholarly literature. The year 1 C.E. is the same as the year 1 A.D. and 1 B.C.E. is the same as the year 1 B.C.
Try converting dates using the Calendar Converter.