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The traditional Chinese calendar is a lunisolar calendar, combining the solar, lunar, and other cycles for various social and agricultural purposes. More recently, in China and Chinese communities the Gregorian calendar has been adopted and adapted in various ways, and is generally the basis for standard civic purposes, though also incorporating traditional lunisolar holidays. Also, there are many types and subtypes of the Chinese calendar, partly reflecting developments in astronomical observation and horology, with over a millennium's worth of history. The major modern form is the Gregorian calendar-based official version of Mainland China, though diaspora versions are also notable in other regions of China and Chinese-influenced cultures; however, aspects of the traditional lunisolar calendar remain popular, including the association of the twelve animals of the Chinese Zodiac in relation to months and years.
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon. This means that the lunar hemisphere facing Earth—the near side—is completely sunlit and appears as an approximately circular disk. The full moon occurs roughly once a month.
A lunar calendar is a calendar based on the monthly cycles of the Moon's phases, in contrast to solar calendars, whose annual cycles are based on the solar year. The most widely observed purely lunar calendar is the Islamic calendar. A purely lunar calendar is distinguished from a lunisolar calendar, whose lunar months are brought into alignment with the solar year through some process of intercalation – such as by insertion of a leap month. The details of when months begin vary from calendar to calendar, with some using new, full, or crescent moons and others employing detailed calculations.
A lunisolar calendar is a calendar in many cultures, incorporating 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 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 some cases ordinary years consist of twelve months but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leap month.
A month is a unit of time, used with calendars, that is approximately as long as a natural orbital period of the Moon; the words month and Moon are cognates. The traditional concept of months arose with the cycle of Moon phases; such lunar months ("lunations") are synodic months and last approximately 29.53 days, making for roughly 12.37 such months in one Earth year. From excavated tally sticks, researchers have deduced that people counted days in relation to the Moon's phases as early as the Paleolithic age. Synodic months, based on the Moon's orbital period with respect to the Earth–Sun line, are still the basis of many calendars today and are used to divide the year.
A lunar phase or Moon phase is the apparent shape of the Moon's directly sunlit portion as viewed from the Earth. In common usage, the four major phases are the new moon, the first quarter, the full moon and the last quarter; the four minor phases are waxing crescent, waxing gibbous, waning gibbous, and waning crescent. A lunar month is the time between successive recurrences of the same phase: due to the eccentricity of the Moon's orbit, this duration is not perfectly constant but averages about 29.5 days.
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the naked eye, except when it is silhouetted against the Sun during a solar eclipse.
A year is the time taken for astronomical objects to complete one orbit. For example, a year on Earth is the time taken for Earth to revolve around the Sun. Generally, a year is taken to mean a calendar year, but the word is also used for periods loosely associated with the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. The term can also be used in reference to any long period or cycle, such as the Great Year.
The term dark moon describes the last visible crescent of a waning Moon. The duration of a dark moon varies between 1.5 and 3.5 days, depending on its ecliptic latitude. In current astronomical usage, the new moon occurs in the middle of this dark period, when the Moon and Sun are in conjunction. This definition has entered popular usage, so that calendars will typically indicate the date of the "new moon" rather than the "dark moon".
As a moveable feast, the date of Easter is determined in each year through a calculation known as computus. Easter is celebrated on the first Sunday after the Paschal full moon. 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.
A blue moon refers either to the presence of a second full moon in a calendar month, to the third full moon in a season containing four, or to a moon that appears blue due to atmospheric effects.
The Attic calendar or Athenian calendar is the lunisolar calendar beginning in midsummer with the lunar month of Hekatombaion, in use in ancient Attica, the ancestral territory of the Athenian polis. It is sometimes called the Greek calendar because of Athens's cultural importance, but it is only one of many ancient Greek calendars.
The September equinox is the moment when the Sun appears to cross the celestial equator, heading southward. Because of differences between the calendar year and the tropical year, the September equinox may occur from September 21 to 24.
A total lunar eclipse occurred from 5:27 to 11:06 UTC on 21 December 2010, coinciding with the date of the Winter solstice in the Northern Hemisphere and Summer solstice in the Southern Hemisphere. It was visible in its entirety as a total lunar eclipse in North and South America, Iceland, Ireland, Britain and northern Scandinavia.
A total lunar eclipse occurred on 31 January 2018. The Moon was near its perigee on 30 January and as such may be described as a "supermoon", when the Moon's distance from the Earth is less than 360,000 km. The previous supermoon lunar eclipse was in September 2015.
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical cultures whose number of seasons varies.
The term Mongolian calendar refers to a number of different calendars, the oldest of which was a solar calendar. The beginning of the year was autumn. The year was divided into 4 seasons. The seasons begin at the equinoxes and the solstices of the sun. This calculation was changed in 1211, and the new year was celebrated in the spring. Spring began on March 22.
A supermoon is a full moon or a new moon that nearly coincides with perigee—the closest that the Moon comes to the Earth in its elliptic orbit—resulting in a slightly larger-than-usual apparent size of the lunar disk as viewed from Earth. The technical name is a perigee syzygy or a fullMoon around perigee. Because the term supermoon is astrological in origin, it has no precise astronomical definition.
The Tenpō calendar, officially known as the Tenpō sexagenary unitary calendar, was a Japanese lunisolar calendar. It was published in the Tenpō era (1830–1844) it remained in use throughout the late Edo period, from 1844 to 1872.
The Hindu calendar is based on a geocentric model of the Solar System. A geocentric model describes the Solar System as seen by an observer on the surface of the Earth.
References
- ↑ The earliest source appears to be the 2016 on-line article on "Time and Date" referenced below: it does mention but does not properly refer to "astrology" and "wicca", so this appears to be a recent invention modeled after Blue moon.
- 1 2 3 4 5 6 7 8 9 10 11 "What Is a Black Moon?". Time and Date. Retrieved 3 October 2016.
- 1 2 3 "Black Moon". The Moon FAQs. Retrieved 3 October 2016.
- 1 2 3 4 5 David Harper (2015). "Two New Moons in one month" . Retrieved 3 October 2016.
- 1 2 Sten Odenwald (2004). "Is there a name for the second New Moon in a month?". Ask the Astronomer. Retrieved 3 October 2016.
- ↑ Fraser Cain (24 December 2015). "Black moon". Universe Today. Retrieved 3 October 2016.
- 1 2 3 Joe Rao (30 September 2016). "Black Moon 2016: What It Is (and Why You Can't See It)". Space.com. Retrieved 3 October 2016.
- ↑ Dorothy Morrison (2004). Everyday Moon Magic Spells & Rituals for Abundant Living. Llewellyn Publications. p. 43. ISBN 0-7387-0249-8.
- 1 2 3 "Black Moon". Witchipedia. Archived from the original on 21 October 2019. Retrieved 3 October 2016.
- 1 2 3 4 "Phases of the Moon". Data Services. Astronomical Applications Department, U.S. Naval Observatory. Archived from the original on 30 September 2016. Retrieved 4 October 2016.
- 1 2 3 4 "Phases of the Moon 2000-2049 - Navy.mil" (PDF). US Naval Office. 4 November 1986.
- ↑ "Moonlore". The Celtic Connection. Archived from the original on 16 October 2016. Retrieved 3 October 2016.
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