Ecclesiastical full moon
Encyclopedia
An ecclesiastical full moon is the fourteenth day of a lunar month (an ecclesiastical moon) in an ecclesiastical lunar calendar
. The ecclesiastical lunar calendar spans the year with lunar months of 30 and 29 days which are intended to approximate the observed phases of the moon. Since a true synodic month has a length that can vary from about 29.27 to 29.83 days, the moment of astronomical opposition tends to be roughly 14.75 days after the previous conjunction of the sun and moon. The ecclesiastical full moons of the Gregorian lunar calendar tend to agree with the dates of astronomical opposition, referred to a day beginning at midnight at 0 degrees longitude, to within a day or so. However, the astronomical opposition happens at a single moment for the entire earth: The hour and day at which the opposition is measured as having taken place will vary with longitude. In the ecclesiastical calendar, the 14th day of the lunar month, reckoned in local time, is considered the day of the full moon at each longitude.
Schematic lunar calendars can and do get out of step with the moon. A useful way of checking their performance is to compare the variation of the astronomical new moon (as tabulated in almanacs and many newspapers) with a standard time of 6 A.M. on the last day of a 30 - day month and 6 P.M. (end of day) on the last day of a 29 - day month.
The ecclesiastical full moon is formally the fourteenth day of the ecclesiastical lunar month.
In the medieval period the age of the ecclesiastical moon was announced daily in the office of Prime
at the reading of the martyrology
.
In the Book of Common Prayer
of the Protestant Episcopal Church of the United States of America
, the dates of the paschal full moons for the 19 years of the Gregorian Easter cycle are indicated by the placement of the Golden Number
to the left of the date in March or April on which the paschal full moon falls in that year of the cycle. The same practice is followed in some editions of the Book of Common Prayer of the Church of England.
Computus
Computus is the calculation of the date of Easter in the Christian calendar. The name has been used for this procedure since the early Middle Ages, as it was one of the most important computations of the age....
. The ecclesiastical lunar calendar spans the year with lunar months of 30 and 29 days which are intended to approximate the observed phases of the moon. Since a true synodic month has a length that can vary from about 29.27 to 29.83 days, the moment of astronomical opposition tends to be roughly 14.75 days after the previous conjunction of the sun and moon. The ecclesiastical full moons of the Gregorian lunar calendar tend to agree with the dates of astronomical opposition, referred to a day beginning at midnight at 0 degrees longitude, to within a day or so. However, the astronomical opposition happens at a single moment for the entire earth: The hour and day at which the opposition is measured as having taken place will vary with longitude. In the ecclesiastical calendar, the 14th day of the lunar month, reckoned in local time, is considered the day of the full moon at each longitude.
Schematic lunar calendars can and do get out of step with the moon. A useful way of checking their performance is to compare the variation of the astronomical new moon (as tabulated in almanacs and many newspapers) with a standard time of 6 A.M. on the last day of a 30 - day month and 6 P.M. (end of day) on the last day of a 29 - day month.
The ecclesiastical full moon is formally the fourteenth day of the ecclesiastical lunar month.
In the medieval period the age of the ecclesiastical moon was announced daily in the office of Prime
Prime (liturgy)
Prime, or the First Hour, is a fixed time of prayer of the traditional Divine Office , said at the first hour of daylight , between the morning Hour of Lauds and the 9 a.m. Hour of Terce. It is part of the Christian liturgies of Eastern Christianity, but in the Latin Rite it was suppressed by the...
at the reading of the martyrology
Roman Martyrology
The Roman Martyrology is the official martyrology of the Roman Rite of the Roman Catholic Church. It provides an extensive but not exhaustive list of the saints recognized by the Church.-History:...
.
In the Book of Common Prayer
Book of Common Prayer
The Book of Common Prayer is the short title of a number of related prayer books used in the Anglican Communion, as well as by the Continuing Anglican, "Anglican realignment" and other Anglican churches. The original book, published in 1549 , in the reign of Edward VI, was a product of the English...
of the Protestant Episcopal Church of the United States of America
Episcopal Church (United States)
The Episcopal Church is a mainline Anglican Christian church found mainly in the United States , but also in Honduras, Taiwan, Colombia, Ecuador, Haiti, the Dominican Republic, Venezuela, the British Virgin Islands and parts of Europe...
, the dates of the paschal full moons for the 19 years of the Gregorian Easter cycle are indicated by the placement of the Golden Number
Golden numbers
A golden number is a number assigned to each year in sequence to indicate the year's position in a 19-year Metonic cycle. They are used in the computus and also in the Runic calendar. The golden number of any Julian or Gregorian calendar year can be calculated by dividing the year by 19, taking...
to the left of the date in March or April on which the paschal full moon falls in that year of the cycle. The same practice is followed in some editions of the Book of Common Prayer of the Church of England.
External links
- U.S. Naval Observatory Data Services
- Gregorian ecclesiastical new moons
- The Calendar of the Church Year from the Episcopal Book of Common Prayer. (Paschal full moons are indicated on the calendar pages for March and April.)