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Epacts
The epact ( la, epactae, from grc, ἐπακται ἡμεραι () = added days), used to be described by medieval computists as the age of a phase of the Moon in days on 22 March; in the newer Gregorian calendar, however, the epact is reckoned as the age of the ecclesiastical moon on 1 January. Its principal use is in determining the date of Easter by computistical methods. It varies (usually by 11 days) from year to year, because of the difference between the solar year of 365366 days and the lunar year of 354355 days. Lunar calendar Epacts can also be used to relate dates in the lunar calendar to dates in the common solar calendar. Solar and lunar years A solar calendar year has 365 days (366 days in leap years). A lunar calendar year has 12 lunar months which alternate between 30 and 29 days for a total of 354 days (in leap years, one of the lunar months has a day added; since a lunar year lasts a little over days, a leap year arises every second or third year rathe ...
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Computus
As a moveable feast, the date of Easter is determined in each year through a calculation known as (). Easter is celebrated on the first Sunday after the Paschal full moon, which is the first full moon on or after 21 March (a fixed approximation of the March equinox). Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the Julian or Gregorian calendar. The complexity of the algorithm arises because of the desire to associate the date of Easter with the date of the Jewish feast of Passover which, Christians believe, is when Jesus was crucified. It was originally feasible for the entire Christian Church to receive the date of Easter each year through an annual announcement by the Pope. By the early third century, however, communications in the Roman Empire had deteriorated to the point that the church put great value in a system that would allow the clergy to determine ...
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Date Of Easter
As a moveable feast, the date of Easter is determined in each year through a calculation known as (). Easter is celebrated on the first Sunday after the Paschal full moon, which is the first full moon on or after 21 March (a fixed approximation of the March equinox). Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the Julian or Gregorian calendar. The complexity of the algorithm arises because of the desire to associate the date of Easter with the date of the Jewish feast of Passover which, Christians believe, is when Jesus was crucified. It was originally feasible for the entire Christian Church to receive the date of Easter each year through an annual announcement by the Pope. By the early third century, however, communications in the Roman Empire had deteriorated to the point that the church put great value in a system that would allow the clergy to determine ...
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Computus
As a moveable feast, the date of Easter is determined in each year through a calculation known as (). Easter is celebrated on the first Sunday after the Paschal full moon, which is the first full moon on or after 21 March (a fixed approximation of the March equinox). Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the Julian or Gregorian calendar. The complexity of the algorithm arises because of the desire to associate the date of Easter with the date of the Jewish feast of Passover which, Christians believe, is when Jesus was crucified. It was originally feasible for the entire Christian Church to receive the date of Easter each year through an annual announcement by the Pope. By the early third century, however, communications in the Roman Empire had deteriorated to the point that the church put great value in a system that would allow the clergy to determine ...
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Lunisolar Calendar
A lunisolar calendar is a calendar in many cultures, combining lunar calendars and solar calendars. The date of Lunisolar calendars therefore indicates both the Moon phase and the time of the solar year, that is the position of the Sun in the Earth's sky. If the sidereal year (such as in a sidereal solar calendar) is used instead of the solar year, then the calendar will predict the constellation near which the full moon may occur. As with all calendars which divide the year into months there is an additional requirement that the year have a whole number of months. In this case ordinary years consist of twelve months but every second or third year is an embolismic month, embolismic year, which adds a thirteenth Intercalation (timekeeping), intercalary, embolismic, or leap month. Their months are based on the regular cycle of the Moon's lunar phase, phases. So lunisolar calendars are lunar calendars with – in contrast to them – additional Intercalation (timekeeping), inter ...
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Gregorian Calendar
The Gregorian calendar is the calendar used in most parts of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun. The rule for leap years is: There were two reasons to establish the Gregorian calendar. First, the Julian calendar assumed incorrectly that the average solar year is exactly 365.25 days long, an overestimate of a little under one day per century, and thus has a leap year every four years without exception. The Gregorian reform shortened the average (calendar) year by 0.0075 days to stop the drift of the calendar with respect to the equinoxes.See Wikisource English translation of the (Latin) 1582 papal bull '' Inter gravissimas''. Second, ...
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Gregorian Reform Of The Calendar
The Gregorian calendar is the calendar used in most parts of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun. The rule for leap years is: There were two reasons to establish the Gregorian calendar. First, the Julian calendar assumed incorrectly that the average solar year is exactly 365.25 days long, an overestimate of a little under one day per century, and thus has a leap year every four years without exception. The Gregorian reform shortened the average (calendar) year by 0.0075 days to stop the drift of the calendar with respect to the equinoxes.See Wikisource English translation of the (Latin) 1582 papal bull ''Inter gravissimas''. Second, in ...
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Dionysius Exiguus
Dionysius Exiguus (Latin for "Dionysius the Humble", Greek: Διονύσιος; – ) was a 6th-century Eastern Roman monk born in Scythia Minor. He was a member of a community of Scythian monks concentrated in Tomis (present day Constanța, Romania), the major city of Scythia Minor. Dionysius is best known as the inventor of Anno Domini (AD) dating, which is used to number the years of both the Gregorian calendar and the (Christianised) Julian calendar. Almost all churches adopted his ''computus'' for the dates of Easter. From around the year 500 until his death, Dionysius lived in Rome. He translated 401 Church canons from Greek into Latin, including the Apostolic Canons and the decrees of the First Council of Nicaea, First Council of Constantinople, Council of Chalcedon, and Council of Sardica, and a collection of the decretals of the popes from Siricius to Anastasius II. These '' Collectiones canonum Dionysianae'' had great authority in the West, and they continue to gu ...
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Aloisius Lilius
Aloysius Lilius (c. 1510 – 1576), also variously referred to as Luigi Lilio or Luigi Giglio, was an Italian doctor, astronomer, philosopher and chronologist, and also the "primary author" who provided the proposal that (after modifications) became the basis of the Gregorian Calendar reform of 1582.For name-variants and a few biographical details (including citation to a biography published in 1963) see page 206 in: A Ziggelaar (1983)"The papal bull of 1582 promulgating a reform of the calendar" pages 201–239 in G. V. Coyne (ed.), ''The Gregorian Reform of the Calendar: Proceedings of the Vatican conference to commemorate its 400th anniversary'' (Vatican City: Specola Vaticana), 1983. The crater Lilius on the Moon is named after him, as is the asteroid 2346 Lilio. In computer science, the Lilian date is the number of days since the adoption of the Gregorian calendar on 15 October 1582. Life and work Not much is known about the early life of Lilius/Lilio/Giglio. It is known th ...
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Golden Number (time)
Golden number may mean: * Golden number (time), a number assigned to a calendar year denoting its place in a Metonic cycle * Golden ratio, an irrational mathematical constant with special properties in arts and mathematics ** Fibonacci number In mathematics, the Fibonacci numbers, commonly denoted , form a sequence, the Fibonacci sequence, in which each number is the sum of the two preceding ones. The sequence commonly starts from 0 and 1, although some authors start the sequence from ...
, a sequence of numbers which converges on the golden ratio {{Disambig ...
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Bede
Bede ( ; ang, Bǣda , ; 672/326 May 735), also known as Saint Bede, The Venerable Bede, and Bede the Venerable ( la, Beda Venerabilis), was an English monk at the monastery of St Peter and its companion monastery of St Paul in the Kingdom of Northumbria of the Angles (contemporarily Monkwearmouth–Jarrow Abbey in Tyne and Wear, England). Born on lands belonging to the twin monastery of Monkwearmouth–Jarrow in present-day Tyne and Wear, Bede was sent to Monkwearmouth at the age of seven and later joined Abbot Ceolfrith at Jarrow. Both of them survived a plague that struck in 686 and killed a majority of the population there. While Bede spent most of his life in the monastery, he travelled to several abbeys and monasteries across the British Isles, even visiting the archbishop of York and King Ceolwulf of Northumbria. He was an author, teacher (Alcuin was a student of one of his pupils), and scholar, and his most famous work, ''Ecclesiastical History of the English People ...
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