Depiction of the 19 years of the Metonic cycle as a wheel, with the Julian date of the Easter New Moon, from a 9th-century computistic manuscript made in St. Emmeram's Abbey (Clm 14456, fol. 71r)For example, by the 19-year Metonic cycle, the full moon repeats on or near Christmas between 1711 and 2300.[1][2] A small horizontal libration is visible comparing their appearances. A red color shows full moons that are also lunar eclipses.
The Metonic cycle or enneadecaeteris (from Ancient Greek: ἐννεακαιδεκαετηρίς, from ἐννεακαίδεκα, "nineteen") is a period of almost exactly 19 years after which the lunar phases recur at the same time of the year. The recurrence is not perfect, and by precise observation the Metonic cycle defined as 235 synodic months is just 2 hours, 4 minutes and 58 seconds longer than 19 tropical years. Meton of Athens, in the 5th century BC, judged the cycle to be a whole number of days, 6,940.[3] Using these whole numbers facilitates the construction of a lunisolar calendar.
A tropical year (about 365.24 days) is longer than 12 lunar months (about 354.36 days) and shorter than 13 of them (about 383.90 days). In a Metonic calendar (a type of lunisolar calendar), there are twelve years of 12 lunar months and seven years of 13 lunar months.
^"Rare Full Moon on Christmas Day". NASA. 17 December 2015. Archived from the original on 8 November 2023.
^Skilling, Tom (20 December 2015). "Ask Tom: How unusual is a full moon on Christmas Day?". Chicago Tribune. Archived from the original on 22 December 2015.
The Metoniccycle or enneadecaeteris (from Ancient Greek: ἐννεακαιδεκαετηρίς, from ἐννεακαίδεκα, "nineteen") is a period of almost exactly 19 years after...
leap months are now added in 7 out of every 19 years according to the Metoniccycle. Nowadays, Hebrew years are generally counted according to the system...
sidereal year. Instead, they employ their versions of the Metoniccycle. However, since the Metoniccycle is not very accurate for sidereal years, the Southeast...
years, as an improvement of the 19-year Metoniccycle. A century before Callippus, Meton had described a cycle in which 19 years equals 235 lunations,...
version of the Metoniccycle. The calendar therefore has to reconcile the sidereal years of the Hindu calendar with the Metoniccycle's near tropical years...
years, before the lunar new year on 1 Nisan. Later Jews adopted the Metoniccycle to predict future intercalations. A possible consequence of this intercalation...
calendars have 7 leap months in every cycle of 19 years (called a 'Metoniccycle'). The Babylonians applied the 19-year cycle in the late sixth century BCE....
19-year Metoniccycle, which he introduced in 432 BC into the lunisolar Attic calendar. Euphronios says that Colonus was Meton's deme. The Metonic calendar...
a version of the Metoniccycle. The calendar therefore has to reconcile the sidereal years of the Hindu calendar with Metoniccycle's tropical years by...
years, 19 years" representing the Callippic and Metoniccycles. Also written is "223" for the Saros cycle. On another one of its fragments, it is written...
series active. Octon 8 eclipse seasons, 1⁄5 of the Metoniccycle, and a fairly decent short eclipse cycle, but poor in anomalistic returns. Each octon in...
is the second of four Metoniccycle lunar eclipses on the same date, September 7, each separated by 19 years: The Metoniccycle repeats nearly exactly...
next occur on March 25, 2043. The Metoniccycle repeats nearly exactly every 19 years and represents a Saros cycle plus one lunar year. Because it occurs...
15 Metoniccycles to the existing 13 Metoniccycles of the Diocletian Era (15×19 + 13×19 = 532) to obtain an entire 532 year medieval Easter cycle, whose...
Saros cycle 146. This eclipse is the last of four Metoniccycle lunar eclipses on the same date, 28–29 October, each separated by 19 years: The metonic cycle...
Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term was coined and...
cycle, which itself was proposed as a correction to the 19-year-long Metoniccycle. He may have published it in the book "On the Length of the Year" (Περὶ...
and then later systematically according to what is now known as the Metoniccycle. Month names from the Babylonian calendar appear in the Hebrew calendar...
years), the Callipic cycle (which is four Metoniccycles and more accurate), the Saros cycle and the Exeligmos cycles (three Saros cycles for the accurate...
form of brass tobacco boxes. The calendar is based on the 19 year-long Metoniccycle, correlating the Sun and the Moon, but the calendar does not prove knowledge...
(time), a number assigned to a calendar year denoting its place in a Metoniccycle Golden ratio, an irrational mathematical constant with special properties...
95-years cycle consisted of five sub cycles of 19 years. The sub cycle of 19 years is called as MetonicCycle in the modern times. The cycle of 19 years...
The Sothic cycle or Canicular period is a period of 1,461 Egyptian civil years of 365 days each or 1,460 Julian years averaging 365+1⁄4 days each. During...
equinox) for the first time since 1991, after a period known as the Metoniccycle. All full moons rise around the time of sunset. Since the Moon moves...
alternating between each saros series. The Metoniccycle repeats nearly exactly every 19 years and represents a Saros cycle plus one lunar year. Because it occurs...
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