Endless calendar
.png)
A perpetual calendar is a calendar (an overview that assigns the weekday name to a calendar date within a selected period of time ) in which the weekday belonging to a date can be read off for any year.
Perpetual calendars are also used to describe tables that enable the day of the week to be determined on a given date (→ calendar calculation ). Also tables for display of holidays , from one specific day or from a certain date (eg. As in appliances, computers) are grouped under this designation. Furthermore, the adjective " eternal " is used in calendars in computer programs for selected periods of time - mostly years - , in lexicons also "everlasting", "permanent" or " universal -".
The term perpetual calendar is also used in complex movements of pocket or wristwatches ( grande complications ) to describe a calendar mechanism integrated in a watch that "continuously" displays the correct date and either the different lengths of all months ( half-way calendar ) or only those of the months with 30 or 31 days ( February must then be corrected manually; annual calendar ). More elaborate movements also take into account the four-yearly return of leap years , often even the corresponding exceptions in the centuries ( perpetual calendar ), but only until February 28, 2100.
Certain calendar reforms or drafts are also known as perpetual calendars, for example the world calendar or the international perpetual calendar (IFC).
In addition to displaying the day of the week and public holidays , a calendar for daily use can also contain a lot more information; In the following, however, only the basic calendar - i.e. the basic structure - is dealt with.
Perpetual Gregorian calendar
The starting point for the presentation of perpetual calendars is the following ten-year calendar (updated; from 2015).
The ten-year calendar is also an excerpt from the C. H. Beck permanent calendar below.
In which year does a congruence occur? In the leap year 1992 January 1st is a Wednesday; in which leap year is January 1st a Wednesday again? The solution is given by using the available data. Add five days of the week from the base leap year day of the week or subtract two days of the week to get to the next leap year. Accordingly, the weekday of January 1st is: 1992 Wednesday, 1996 Monday, 2000 Saturday, 2004 Thursday, 2008 Tuesday, 2012 Sunday, 2016 Friday, 2020 Wednesday. 1992 corresponds to the year 2020. The conclusion is therefore logical: A basic calendar can always be used again after 28 years. The respective common years in between are repeated every 28 years. The well-known congruence can be seen in the example of the path taken here.
A calendar for longer periods of time is represented by first creating a calendar for 28 years according to the above pattern. This is identical with regard to the weekday sequence for the following 28 years (small cycle: 7 weekdays × 4 years leap day rhythm). This process is repeated until we reach the desired timeframe. You can freely choose which year we start with. The "moving on" of the years - the first of January - by one day or two days after a leap year is known . This results from dividing 365 days / common year divided by 7 days / week = XY, with the remainder 1 day . This makes it clear: a common year always ends on the weekday of January 1st, a leap year accordingly on the following day of the week.
Note : The result of division XY = 52 weeks has no meaning with regard to the calendar week .
Pope Gregory XIII certain u. a. in principle that on Thursday, October 4th, 1582 jul. immediately Friday October 15th, 1582 greg. as the beginning of the new calendar calculation and only the century-year calendars may have a leap day if their full year numbers are divisible by 400 (without remainder). The common year calendars are classified for the years 1700/1800/1900 in the perpetual Gregorian calendar design.
For the years that follow the respective centenary year calendar , it should be noted that there is always an annual calendar which is three years before a leap year in order to do justice to the above-mentioned fact - moving on to January 1st - and to fit into the leap day rhythm reach.
After the construction of a perpetual Gregorian calendar , it is determined that the sequence of annual calendars is repeated congruently after 400 years. Accordingly, the respective blocks are superimposed in the illustration from 1600 onwards.
Gregorian calendar from Oct. 15, 1582
Gregorian Calendar in Mandarin (Chinese)
Eternal Gregorian. Perpetual calendar in English
Perpetual Calendar Calendrier perpétuel Gregorian in French
Eternal Gregorian calendar Вечный календарь in Russian
Perpetual calendar -Wiezcny kalendarz gregorianski- in Polish
Domowina calendar from 1800 to 2100
Perpetual Julian calendar
Now the days of the week are assigned to the dates before the introduction of the Gregorian calendar .
Base
Calendars were not as common in the past as they are today. The people were informed by the authorities what the date was.
Karl Mütz writes: “The priests probably did not fully understand the calendar reform [meaning Julius Caesar's]. You did not insert the leap day after three years, but already in the third year […]. This error was corrected [...] by Gaius Octavianus [Emperor Augustus] by replacing the leap days from 8 BC. To 8 AD were deleted ”.
At Grotefend it is stated that January 1st of year 1 was a Saturday (Saturday). This can only be considered correct if the above is neglected.
Neither here nor at the time of the previous correction of the Roman calendar by Julius Caesar in 46 BC. There is talk of a weekday designation. In contrast to the proclamation of the Gregorian calendar; Thursday, October 4, 1582, was immediately followed by Friday, October 15, 1582. At the last-mentioned point in time, the use of the weekday names had already stabilized. Everything that happened before, in this regard, is incomprehensible.
Heinz Zemanek writes in the calendar and chronology :
“The week is one of the oldest calendar terms and is the longest undisturbed time order. At the time of Christ it prevailed in the Roman Empire and has been preserved in uninterrupted succession ever since. The week is from the Middle East, but nobody knows when it came in use - so nobody knows when the first Saturday was. But you can project the weekly period as far back as you like, and many chronologists have done that ”.
Hannes E. Schlag describes the problem in "One day too much":
"The week, a man-made period of time"
"An unsolved question is when ... the 7-day week took place. In the first century BC, the seven-day week was already common in part of the Roman Empire."
Hermann Grotefend in "Taschenbuch der Zeitrechnung":
"It was only in the Middle Ages that the name of the day began to stabilize. At that time, with reference to the previous or just past festive or saint days with regard to their designation (ie not yet: Mon or Tue / Wed ...)".
In summary, it can be said that it does not seem possible to find a clear statement in the gray past; the basis for assigning the day of the week to the date is the introduction of the Gregorian calendar , not the introduction of the Julian calendar. For this reason, it also makes more sense to deal with the structure of the Julian Perpetual Calendar according to that of the Gregorian, although historically the order in which it was applied was reversed.
construction
The construction of the perpetual Julian calendar begins by assigning the previously described assignment with January 1st of the year 1 AD to the weekday "Sa" and assigning this year column "01" to a year column of the month and weekday block - taken from the Gregorian calendar , in which the weekday "Sa" is three years before a leap year (since the year 4 after Chr. must be a leap year). It does not matter which representation is actually used; the system of the eternal - here "Gregorian calendar" - can be rotated and rolled. That means, which beginning year is classified where exactly is irrelevant. Now the following years are assigned in sequence to the weekday columns - as before - up to the year on the right edge (see example used). If 28 columns are filled, the next year column is started from the beginning on the left, and so on, and so on, until the first block from the year 1 AD to the year 100 AD (a leap year) is filled.
In order to be able to clearly assign the individual years or their blocks to the centuries, a blank line has been inserted. After the 7th block has been created, the 8th century block, which is congruent with the 1st century, begins and shows the 700-year repetition of the Julian calendar.
The perpetual calendar
The Julian and Gregorian calendar displays are combined in one copy. The congruence of the years 1600 jul. / 2000 jul. with the years 1600 greg. / 2000 greg. assumed and the data classified accordingly.
Why does the term “perpetual calendar” appear to be justified as a solution for the future?
The additional leap day regulation that will become necessary in approx. 3300 years after the Gregorian calendar has been called up includes the elimination of a previously regular leap day. Let us assume that those responsible then decide to throw out this leap day in the year 4800 - a year-end calendar gregor.
The 1st of January of this year has the weekday "Sa" (see index "e"). Due to the omission of the leap day, we now assign the common year 4800 to index “h”. The year 4801 begins with “So” and classifies this year at the beginning of the 7th century in Julian -lower block-. Only here is January 1st three years before a leap year. The fourth year after the ejection of a previously regular leap day must again be a leap year.
The same procedure is possible for any other assumed point in time when a leap day is no longer applicable.
This practically proves: The Gregorian calendar as a flexible Julian calendar fulfills all the requirements of the necessary leap day regulation for all times. It is not only correct again for millennia, but it is also able to compensate for changes in the earth's orbit, the inclination angle of the earth's axis and other time factors of celestial mechanics not mentioned in this article without leaving the calendar system, which is the ingenious achievement of the physician and astronomer Aloisius Lilius emphasizes who created the calendar in principle. The question remains whether it might seem more important to future generations, for example to introduce the Orthodox calendar or the Mädler calendar because of the better approximation to the solar year , or to give preference to a world calendar . However , it is doubtful whether the respective advantages outweigh the enormous effort involved in changing a calendar .
The people who, after the calendar change, had to note two dates on various documents for one and the same day - the date according to the Julian calendar and the date according to the Gregorian calendar - had to make a conversion . The continuation of the weekday designation - no interruption of the weekday sequence with the introduction of Gregory. Calendar serves as a means of checking the correctness of the result.
According to the copy of the birth certificate, the date of birth was January 31, 1881 July. or on February 12, 1881 greg. . The day of the week is consistently Saturday. Ditto the day of issue of the document: August 25, 1881 jul. or September 6, 1881 greg. , Weekday: Tuesday. Difference: twelve counting days.
century
Assuming that there was no year "zero" in the calendar , the first century begins with the first day of year 1; marked here with 01. 100 years will be over when December 31 of the year 100 is over.
This is not in dispute; all secular years - those with the zeros - are the end or closing years of the centuries, not the beginning years.
Return of the annual calendar
How do the individual annual calendars (basic calendars) repeat themselves over the centuries?
The following knowledge can be taken from the perpetual calendars without any doubt. A common annual calendar is congruent with the one that begins with the same day of the week, analogously to the leap year calendar.
If a common year is three years before a leap year, it returns after six years and then twice after eleven years (6 + 11 + 11 = 28), if it is two years before a leap year, the calendar returns after eleven years, after six years and again after eleven years (11 + 6 + 11 = 28), it is a year before a leap year, after eleven years, after another eleven years and after six years (11 + 11 + 6) again. It is easy to see that there are only 14 annual calendars , seven for common years and seven for leap years. Once again, one finds that leap year calendars only repeat themselves after 28 years.
history
The perpetual calendars have developed most diverse in modern times in the Soviet Union . The reasons for this development can be found in the introduction of the revolution calendar by the Council of People's Commissars in November 1929, with which the weekday designations were still valid, but lost their meaning. Because there was broken five days - a week with 12 months of 30 days each, and five non-working days. This was followed by the transition to the six-day week in November 1931 and finally the seven-day week again in 1940 .
In 1940 the old weekday system was reintroduced and the importance of the calendar - especially the perpetual calendar - increased sharply. The following table calendar was considered the most convenient long-term calendar table in the Soviet Union .
Julian and Gregorian calendars for 28 centuries
|
regulate
In the table below there are the centuries (first two digits of the year), on the left according to the Julian system, on the right according to the Gregorian system . In the upper part - here next to it - are the years in the century (last two digits of the year). At the intersection of the century line and the year column is the Sunday letter for the year in question. The months are under the sample calculation . Months that begin with the same day of the week are on one line. The starting point is now the column of the Sunday letter found above in the month line. The day of the week is at the intersection with the line for the day of the month . Leap years are shown in red . The year " 00 " is an exception. It is always a leap year in the Julian calendar. In the Gregorian calendar only if the full year is divisible by 400 without a remainder. The years 1700, 1800, 1900, 2100… Gregorian are therefore not leap years. The year 1 AD is to be assigned to the century " 0 ". |
Years in the century |
example 1
Determination of the weekday for March 31, 2006: At the intersection of the year column "06" with Gregorian 20 from the Centuries table is the Sunday letter "A". Next, look for the Sunday letter "A" in the line for March (in the months table ). At the intersection of this column with the line for day 31 of the month is Friday. Example 2
Weekday determination for January 1st 45 BC Chr .: From the fact that there is no year zero in the normal Julian calendar and therefore the year 1 BC corresponds to the year 1 AD. The year 45 BC. Chr. The arithmetical year "−44", this in turn can be represented as "−100 + 56". At the intersection of the year column “56” with the line “-1” is the Sunday letter “B”. The year 45 BC BC was a leap year, so look for the entry "January" (leap year - red ) in the months table on the right . In this line you go from the Sunday letter "B" down to the line with the day of the month 1 and find Friday. Example 3
Julian calendar January 1, 1900: The year 00 julian. is a leap year, at the intersection with julian. In the 19th century there is the Sunday letter "A". Based on "January" (leap year - red ) "A" results in Saturday for day 1 of the month. Example 4
Gregorian January 1, 1900: The year 00 Gregn. is a common year, at the intersection with Gregorian. In the 19th century there is the Sunday letter "G". Starting from “January” and “G”, day 1 of the month is Monday. |
||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 00 | 01 | 02 | 03 | 04 | 05 | |||||||||||||||
| 06 | 07 | 08 | 09 | 10 | 11 | |||||||||||||||
| 12 | 13 | 14th | 15th | 16 | ||||||||||||||||
| 17th | 18th | 19th | 20th | 21st | 22nd | |||||||||||||||
| 23 | 24 | 25th | 26th | 27 | ||||||||||||||||
| 28 | 29 | 30th | 31 | 32 | 33 | |||||||||||||||
| 34 | 35 | 36 | 37 | 38 | 39 | |||||||||||||||
| 40 | 41 | 42 | 43 | 44 | ||||||||||||||||
| 45 | 46 | 47 | 48 | 49 | 50 | |||||||||||||||
| 51 | 52 | 53 | 54 | 55 | ||||||||||||||||
| 56 | 57 | 58 | 59 | 60 | 61 | |||||||||||||||
| 62 | 63 | 64 | 65 | 66 | 67 | |||||||||||||||
| 68 | 69 | 70 | 71 | 72 | ||||||||||||||||
| 73 | 74 | 75 | 76 | 77 | 78 | |||||||||||||||
| 79 | 80 | 81 | 82 | 83 | ||||||||||||||||
| 84 | 85 | 86 | 87 | 88 | 89 | |||||||||||||||
| 90 | 91 | 92 | 93 | 94 | 95 | |||||||||||||||
| 96 | 97 | 98 | 99 | |||||||||||||||||
| Number of centuries | Sunday letters | Months | ||||||||||||||||||
| Julian | greg. | |||||||||||||||||||
| -4 | 3 | 10 | 17th | - | - | F. | E. | D. | C. | B. | A. | G | Jan. | April | July | |||||
| -3 | 4th | 11 | 18th | 15th | 19th | G | F. | E. | D. | C. | B. | A. | Jan. | Oct | ||||||
| -2 | 5 | 12 | 19th | 16 | 20th | A. | G | F. | E. | D. | C. | B. | May | |||||||
| -1 | 6th | 13 | 20th | - | - | B. | A. | G | F. | E. | D. | C. | Feb | Aug | ||||||
| 0 | 7th | 14th | 21st | 17th | 21st | C. | B. | A. | G | F. | E. | D. | Feb | March | Nov | |||||
| 1 | 8th | 15th | 22nd | - | - | D. | C. | B. | A. | G | F. | E. | June | |||||||
| 2 | 9 | 16 | 23 | 18th | 22nd | E. | D. | C. | B. | A. | G | F. | Sept | Dec | ||||||
| Days of the month | Days of the week |
31 days - Jan |
||||||||||||||||||
| 1 | 8th | 15th | 22nd | 29 | Mon | Tuesday | Wed | do | Fr. | Sat | So | |||||||||
| 2 | 9 | 16 | 23 | 30th | Tuesday | Wed | do | Fr. | Sat | So | Mon | |||||||||
| 3 | 10 | 17th | 24 | 31 | Wed | do | Fr. | Sat | So | Mon | Tuesday | |||||||||
| 4th | 11 | 18th | 25th | do | Fr. | Sat | So | Mon | Tuesday | Wed | ||||||||||
| 5 | 12 | 19th | 26th | Fr. | Sat | So | Mon | Tuesday | Wed | do | ||||||||||
| 6th | 13 | 20th | 27 | Sat | So | Mon | Tuesday | Wed | do | Fr. | ||||||||||
| 7th | 14th | 21st | 28 | So | Mon | Tuesday | Wed | do | Fr. | Sat | ||||||||||
Note: From the point of view of the confused year and the Augustan correction - the determination of the weekday before the year 8 is only hypothetical.
This calendar table largely corresponds to W. Bogatyrjows "Perpetual Calendar" from 1931 (таблицу В. Богатырева), derived from "An Eternal Calendar" by S. Emi, and based on the 1957 published "Table Calendar for the 20th Century" of an unknown Author (Табель-календарь вожатого на XX век) edited.
New perpetual calendars kept appearing, and cardboard calendars began to be mass-produced . However, these cardboard calendars did not have the lifespan required for a product intended for eternity, so that in the 1960s the company switched to making perpetual calendars from aluminum ; these were mainly constructions with turntables. In the 1970s, they went back to making the turntable calendars out of cardboard, which, however, caused demand to decline, so that calendar tables were increasingly being published again.
The collapse of the Soviet Union also resulted in the disappearance of the perpetual calendar. Most of the remaining ones only worked until the year 2000, so that afterwards they almost completely disappeared. Today computers are mainly used to calculate the day of the week .
Further algorithms for determining the day of the week
For the following examples, the term "calendar" is not justified by definition ; if the desired day of the week has been determined according to the respective instructions, it is by no means certain that the result found is correct, as it cannot be easily checked. You have to believe the result, so to speak, or, after entering the appropriate information into a computer, accept the weekday displayed here as the correct comparison value.
.png)
Devices with moving elements
In 1929 the Russian publisher "Гудок" (Gudok) brought out a metal calendar. It consisted of a rigid base on which two concentric circles were applied, and a rotating disc. The year numbers were arranged on the outer circle, the days of the week on the inner circle, which are repeated four times on the circle. The months were recorded on seven parallel fields on the rigid surface. A disk sector indicated days 1 to 31, above which was a section in which the days of the week were visible.
See also
- Complication (clockwork)
- Orthodox calendar (New Julian calendar)
literature
- H. Grotefend: Pocket book of the time calculation of the German Middle Ages and the modern times. Hahnsche Buchhandlung, Hanover / Leipzig 1915.
- Karl Mütz: Fascination Calendar. Polygon-Verlag, Buxheim Eichstätt 1999, ISBN 3-928671-14-6 .
- Karl Mütz: Calendar day and ... p. 83.
- Perpetual calendar. In: Hannes E. Schlag: One day too many. Verlag Königshausen & Neumann, Würzburg 1998, ISBN 3-8260-1531-2 , pp. 128/129.
- Perpetual weekday calendar. In: Joachim Erlebach: Mathematical leisure hours. 12th edition. De Gruyter, 1964, ISBN 3-11-125868-8 , p. 199/200.
- Heinz Zemanek: Calendar and Chronology. 5th edition. Oldenbourg-Verlag, 1990, ISBN 3-486-20927-2 .
- Jürgen Hamel : Cal. Calculation ... present. Lectures ... No. 62 of the Archenhold Observatory Berlin-Treptow, 1983.
- Strömgren / Strömgren: Textbook of Astronomy. Berlin 1936.
- Ulrich Bastian: Time. The eternal riddle. (= Stars and space. Special 5). Verlag Sterne und Weltraum, Heidelberg 2000, ISBN 3-87973-502-6 . (Leaflet insert)
- Adolf Weniaminowitsch Butkewitsch , Moisei Samoilowitsch Selikson: Perpetual Calendar. (= Small natural science library. Volume 23). BSB BG Teubner Verlagsgesellschaft, Leipzig 1989, ISBN 3-322-00393-0 .
- Hermann Grotefend : Pocket book of the time calculation of the German Middle Ages and the modern times. 13th edition. Hahn, Hannover 1991, ISBN 3-7752-5177-4 .
- Tax advisor calendar 2013. C. H. Beck, Munich, ISSN 0177-7203 , ISBN 978-3-406-62919-8 , p. 287.
Web links
- Wikitable perpetual calendars (English)
- Perpetual calendar (based on Theodor Wagner) (PDF file; 839 kB)
Individual evidence
- ^ Gisbert L. Brunner : wristwatches with a perpetual calendar. In: Old clocks. No. 4, 1985, pp. 41-61.
- ↑ the same: The perpetual calendar - homage to time. (Brochure for Audemars Piguet) Geneva / Bad Soden 1994.
- ^ Helmut Kahlert , Richard Mühe , Gisbert L. Brunner , Christian Pfeiffer-Belli: wrist watches: 100 years of development history. Callwey, Munich 1983; 5th edition, ibid 1996, ISBN 3-7667-1241-1 , p. 504.
- ↑ Hannes E. Schlag: One day too many. Verlag Königshausen & Neumann, Würzburg 1998, p. 73.
- ↑ The Roman Calendar. In: Karl Mütz: Fascination Calendar. Polygon-Verlag, Buxheim-Eichstätt 1999, p. 30.
- ^ Heinz Zemanek: Calendar and Chronology. 5th edition. Oldenburg-Verlag, 1990, p. 19.
- ↑ Hannes E. Schlag: One day too many. Publishing house Königshausen & Neumann, Würzburg 1998, p. 20.
- ↑ Hannes E. Schlag: One day too many. Königshausen & Neumann Verlag, Würzburg 1998, p. 21.
- ↑ No quotation; analogously from: Hermann Grotefend: Taschenbuch der Zeitrechnung. Hahnsche Buchhandlung, 1915, p. 16.
- ↑ a b H. Grotefend: Pocket book of the time calculation of the German Middle Ages and the modern times. Hahnsche Buchhandlung, Hanover / Leipzig 1915, pp. 128–129.
- ↑ Heiner Lichtenberg: The adaptable, cyclic, solilunear time counting system of the Gregorian calendar - a scientific masterpiece of the late Renaissance . In: Mathematical Semester Reports , Volume 50, 2003, p. 47.
- ↑ Cf. The 21st Century and the 3rd Millennium : Years of the Gregorian calendar, which is currently in use today, are counted from AD 1. Thus, the 1st century comprised the years AD 1 through AD 100. The second century began with AD 101 and continued through AD 200. By extrapolation we find that the 20th century comprises the years AD 1901-2000. Therefore, the 21st century began with 1 January 2001 and will continue through 31 December 2100.
- ↑ Butkewitsch; Selikson: Perpetual Calendar. P. 18 below / p. 19 above, Teubner Verlagsgesellschaft Leipzig 1974
- ↑ Butkewitsch; Selikson: Perpetual Calendar. P. 77
- ↑ В. Богатырев: Таблица "Вечный календарь" в ст. З. Эми "Вечный календарь". Техника молодежи, H. 11/1940
- ↑ Butkewitsch; Selikson: Perpetual Calendar. P. 78, tab. 24
- ↑ З. Эми: Вечный календарь. Техника молодежи, H. 11/1940
- ↑ Butkewitsch; Selikson: Perpetual Calendar. Calendar from "Книга вожатого на 1957 г.", p. 62 f., Tab. 6
- ↑ Металлический календарь с подвижным диском на 28 лет. М., Гудок 1929 (metal calendar with rotating disc for 28 years)
- ↑ Butkewitsch, Selikson: Perpetual Calendar. P. 44 f.