A calendar is usually called a certain system, with the help of which it becomes possible to differentiate the flow of time at certain intervals, which helps to streamline the course of life. In the entire history of mankind, there were a lot of calendars, and they were based on different principles. In this article we will discuss the main types of calendars, as well as talk about what form our modern time frame can take.
The origin of the word "calendar"
Before proceeding to the description of the types of number systems themselves, we find out where the word denoting them comes from. The term “calendar” etymologically dates back to the Latin verb caleo, which translates as “proclaim”. Another option that has become the source of the word “calendar” is calendarium. The last in ancient Rome was called the debt book. Caleo preserves for us the memory of the fact that in Rome the beginning of each month was especially solemnly proclaimed. As for the debt book, its significance is due to the fact that all interest on debts and loans in Rome was paid on the first day.
The origin of the calendar system
The fact that time flows in a certain circle, mankind has long realized on the basis of cyclically repeating events and phenomena, which are quite a lot. This, for example, the change of day and night, seasons, the rotation of the celestial spheres and so on. Based on them, various types of calendars have evolved over time. The basic unit of time of any of them is a day, which includes one revolution of the Earth around its own axis. Then the moon played an important role in history, the phase change of which forms the so-called synodic month. It is so named in the Greek word "synodos, " which translates as "rapprochement." It is about rapprochement of the sun and the moon in the sky. And finally, the change of the four seasons is a tropical year. Its name comes from the Greek "tropos", that is, "turn".
Why do different peoples living on the same planet have different types of calendars? The answer lies in the fact that the duration of the diurnal circle, the synodic month and the tropical year do not correlate with each other, which provides ample opportunity to choose when compiling the calendar.
Three types of calendar
Based on the described values at different times, attempts were made to draw up a calendar suitable for the life of society. Some of them were guided only by lunar cycles. Thus, lunar calendars appeared. As a rule, they totaled twelve months each, focused only on the movement of the night luminary, and did not correlate with the changing seasons. Others, on the contrary, did their calculations only on the basis of the circle of the seasons, ignoring the moon and its rhythm. This approach gave rise to solar calendars. Still others took into account both cycles - solar and lunar. And, starting from the latter, they tried, one way or another, to reconcile both among themselves. They gave rise to mixed solar-lunar calendars.
Moon calendar
Now we will discuss the nuances of the system of calculating time, based solely on the movement of the moon. The lunar calendar, as already mentioned, is based on the synodic month - the cycle of the lunar phases from the new moon to the full moon. The average duration of such a month is 29.53 days. Therefore, in most lunar calendars, a month lasts 29 or 30 days. Moreover, the year most often consists of twelve months. Thus, it turns out that the length of the year is about 354.36 days. As a rule, it is rounded to 354, while periodically introducing a leap year of 355 days. Do it everywhere in different ways. For example, the Turkish cycle is known, where for eight years there are three leap years. Another option, with a ratio of 30/11, offers the Arab system, on the basis of which the traditional Muslim calendar is compiled.
Since the lunar calendars have nothing to do with the movement of the sun, they gradually diverge from it because of the difference of more than ten days in a year. So, the cycle of the solar calendar in 34 years corresponds to 35 years of the lunar. Despite this inaccuracy, this system satisfied many peoples, especially at an early stage of development, when they were characterized by a nomadic way of life. The moon is easily observable in the sky, and this calendar does not require significant complex calculations. Over time, however, when the role of agriculture increased, its capabilities were not enough - it took a tighter tie of the months to the seasons and the range of agricultural work. This stimulated the development of the solar calendar.
Lunar calendar defect
Besides the fact that the calendar, based entirely on the lunar cycle, diverges significantly from the tropical year, it also has another significant drawback. It consists in the fact that due to a very complex orbit, the duration of the synodic month is constantly changing. The difference can be up to six hours. It should be said that the starting point of the new month in the lunar calendar is not the new moon, which is difficult to observe, but the so-called neomania - the first appearance of the young moon at sunset. This event follows a new moon in 2 or 3 days. In this case, the lack of time depends on the time of the year, the duration of the current month and the location of the observer. This means that a calendar calculated in one place will be completely inaccurate for another area. And in general, no system based on lunar cycles is able to accurately reflect the real movement of the night luminary.
Sunny calendar
The history of the calendar cannot be complete without mentioning the solar cycle. I must say that today it is the main form of reckoning time. It is based on a tropical year consisting of 365.24 days. To make the calculations more accurate, leap years are periodically introduced, which collect the accumulated "surplus" in one "extra" day. There are various leap systems, so many types of calendars based on the movement of the sun are known. The reference point is traditionally considered the vernal equinox. Therefore, one of the requirements of the solar calendar is that every year this event should be on the same date.
The first leopard system was possessed by the Julian calendar. His weak point was that for 128 years he was gaining one extra day, and the equinox shifted, respectively, back. They tried to correct this inaccuracy in various ways. For example, Omar Khayyam proposed a special 33-year cycle, which then became the basis of the Persian calendar. Later, at the initiative of Pope Gregory, the Gregorian calendar was introduced, which is the main civic calendar of modern society. He is also gradually gaining one extra day, but this period stretches from 128 years to 3300.
Another attempt to improve the Julian system was made by Milutin Milankovic. He developed the so-called New-Julian calendar, which was gaining an error per day already at 50, 000 years. This is done thanks to a special rule for century-olds (they can be considered leap years only if divided by 900, the remainder is 2 or 6). The drawback of the Gregorian and New Julian calendars with their accuracy is the fact that the date of the equinox becomes floating, and falls on different days every year.
Solar lunar calendar
Finally, touch the solar-lunar calendar. Its essence is to reconcile in one cycle the movement of the sun with the movement of the moon. To do this, it was necessary to periodically extend the year by one month. Such a year was called embolismic. In Ancient Greece and Babylon, three additional months were introduced over eight years. Its error is one and a half days for the entire eight-year period. According to the history of the calendar, a longer cycle was adopted in China, although it was known both in Babylon and in Greece. Its error is one day for 219 years.
Varieties of calendars
Now let's talk about what kind of calendar exists today. It will be about design, not astronomical features. So, loose-leaf, wall, pocket and tear-off calendars are most in demand today.
Desk calendars
Another name for this type of printing publication is “house”. Although some options may have a different design, including a stand made of plastic. The latter are often integral with the stand for pencils and compartments for paper clips. The bottom line is that the desk calendar is designed so that the month tables are located on different pages that need to be turned over in a timely manner. Together with the calendar, various information or simply beautiful images that are included in the overall design of the room are very conveniently located on them. Such products are used most often in offices, conveniently located in the corner of the desktop. A desk calendar also often serves as a gift or souvenir.
Wall calendar
Many in the kitchen have a calendar attached to a wall, refrigerator door, or door. Wall calendars are very popular because they are convenient to use, and their aesthetic value nowadays makes them a wonderful decoration for the home. Sometimes they combine with the technology of "houses". In this case, wall calendars, as a rule, are real albums dedicated to a particular topic. And the function, in fact, of calculating time fades into the background in them.
Pocket calendar
This type is probably the most common in our time. Pocket calendars are small cards, on the one side of which there is, in fact, a calendar plate, and on the other - some kind of drawing. Very often, such products serve as bookmarks, business cards. Often they are used for advertising purposes. Pocket calendars are a kind of postcards that carry an additional function. They can easily be put in a wallet and carried with you, taking out as needed.
Tear-off calendars
Soviet tear-off calendar is familiar to everyone. Once they were found in almost every home, but today their popularity has somewhat fallen, although they are still common. These products are real books where each page is highlighted for one day of the year. When a new day arrives, the old page comes off. Therefore, it is called tear-off. The back of the page contains some text. As a rule, each such calendar is dedicated to a certain topic and represents a rather informative source within its framework.
Church calendars
A few words should also be said about what a church calendar is, since many people who come to a temple or read church literature encounter a double dating system. In fact, the Church Orthodox calendar refers to the regular Julian calendar. Just over two thousand years, he began to lag behind the real astronomical course of time by almost two weeks. The Catholic Church corrected this, resulting in the appearance of the Gregorian calendar. But the Orthodox did not accept this reform. The Russian Orthodox Church and several other independent jurisdictions, for example, still adhere to the Julian calendar. But most Orthodox churches in the world still switched to the New Julian calendar, which currently coincides with the Gregorian.
The church calendar, therefore, has at least three varieties. In some countries, churches also use their own national calendars. For example, in Egypt, the Coptic chronological system is common. Other religious organizations have their own calendars. For example, Vedic, Buddhist, Islamic, Baha'i and other systems of time organization are known.
