#Lunisolar Calendar

[sag-dab-sar]

"Thus, the Mesopotamian year was, in effect, a solar year squeezed into a lunar strait-jacket."

—The Cultic Calendars of the Ancient Near East by Cohen page 4

Lunisolar calendars in a nutshell.

[brunelsblog]

A tithi is the time it takes for the longitudinal angle between the Moon and the Sun to increase by 12°.

A paksha is a lunar fortnight and consists of 15 tithis.

A māsa is divided into two pakshas.

A ritu (season) is two māsas.

An ayana is three ritus.

A year is two ayanas.

[uwmspeccoll]

Year of the Snake

The past few Lunar New Years we have featured paper-cut designs from our copy of Paper-Cuts in China. This year is the Year of the Snake in the Chinese zodiac calendar, so we present this rather startled-looking snake from Paper-Cuts in China, which features paper cuts of the 12 signs of the Chinese zodiac as well as birds and plants. Lunar New Year falls on the new moon in late January or early February and is based on the Chinese lunisolar calendar. 

This book, for which we have not identified the year or publisher, has text in both Chinese and English. It notes that in 2002, “China’s paper-cut was listed as a ‘world cultural heritage’ by UNESCO.” The commentary to the paper-cut snake says:

The persons born in the year of the snake … have will and spirit to fight all their lives. They are calm, mysterious, romantic, skillful in dealing with things, adept at flow of words, and dapper in appearance. They don't show off their ability, but persist in shade and are able to forge onward in accordance with their plans. They are friendly to others and able to deal with things in different angles. . . . In addition, they can think twice before they act, well know their ability, and dream of creating a successful career by their own power. Finally, there will be a little setback, but the road to happiness is full of hardships.

View other paper cuts from this collection.

View posts from Lunar New Years past.

[supercantaloupe]

hi :) tonight is a full moon and its really pretty. uhhhhh tonight i have been listening to prelude to ecstasy by the last dinner party (the album) ummmm i recently watched Logan (2017) a movie about wolverine xman when he's old and sad and it was quite good and very sad. how are you? ❤️

i have a headache and had to record a bullshit group presentation on zoom that will probably have to get recorded again tomorrow cause it didn't save lol! i should be in bed rn but instead i watched the gastronauts premiere. as a lifelong iron chef fan it comes close to scratching the same itch

[inspofromancientworld]

Ancient Babylonian Calendar

By Lamassu Design Gurdjieff (talk) - Image by Author, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6632777

Calendars are complex structures that help humans know when to do things ranging from ceremony to planting crops. There are theories that the moon was the first calendar, with its predictable changes night after night, then the solstices and equinoxes would have added a regularity to the cycle of the year. The problem comes in that the solar and lunar calendars don't align with each other. A lunar month has about 29.53 days. A solar year is 365.26 days long. These numbers don't evenly go into each other, with each solar year having 12.37 lunar months in it. This leaves about 10.64 days every year that the lunar calendar drifts away from the solar calendar. The phases of the moon (first quarter, full, last quarter, new) are approximately 7.28 days apart and the days of those phases were considered as 'unfavorable' for things like eating of cooked meat or baked bread by the king or priests and doctors working, which gave rise to our modern weeks. With the desire to keep the equinoxes and solstices happening in the same months, it becomes necessary to add an additional month in periodically. Initially, this was done at the ruler's or priest's decree, then a pattern was noticed, leading to lunisolar calendars with a periodicity of either eight (octaeteris) or nineteen years (Metonic cycle).

The Babylonian calendar is one of the oldest lunisolar calendars that we know about that reconciled the solar and lunar cycles as well as other astronomical events. While we have definitive evidence of the calendar being in use shows up about 4000 BCE under the Sumerians, initially, the month was set by observation with the month beginning at the very first sighting of the crescent moon after the new moon, but gradually, patterns were recognized and the beginning of the month was calculated. There is debate when the calendar shifted from observation to calculation, with the standard wisdon saying this happened that calculation could not have happened prior to Thales of Miletus, a Greek mathematician and astronomer who lived around 624-546 BCE, and that the Metonic cycle (which is based on 235 lunar months in 19 solar years) was calculated around 432 BCE by Meton of Athens, a Greek astronomer. The octaeteris is a period of eight years after which the lunar phase will be within a day or two of the same day. It also the period of time after which the Moon and Venus will reach the same positions and phases in the night sky. We're not sure who calculated that cycle, but it is the calendar encoded into the Antikythera mechanism, the oldest known analogue computer know. There is some evidence, however, that the Babylonians could have calculated a month and year and when additional months were necessary to keep solar events in the 'correct' month of the year more than a thousand years prior, most likely based on the octaeteris cycle.

By British Museum - British Museumhttps://www.britishmuseum.org/collection/image/152339001, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=90184887

The Enūma Anu Enlil 𒌓𒀭𒈾𒀭𒂗𒆤𒇲 (which means 'when [the gods] Anu and Enlil […]') was written in the Old Babylonian period, approximately 1950-1595 BCE and revised afterwards through the Kassite period (1595-1157 BCE) gave signs and omens based on astronomical events, including eclipses and other irregular but reliable events in the night sky, down to when exactly in the night the beginning of the crescent of the moon begins to show. Another document, MUL.APIN 𒀯𒀳 (named after 'The Plough' constellation, in the modern constellations of Cassiopeia, Andromeda, and Triangulum), which dates to about 686 BCE, though was probably composed much earlier, around 1000 BCE. It is a catalog of stars, constellations, rising and setting dates of constellations through the year and what path the moon takes. It is the earliest known catalog of the stars as well as how the Babylonian calendar was set up. The months, however, were somewhat idealized, in that a month was 30 ideal days and a year was 360 ideal days, or 12 ideal months. With these ideal divisions, it allows the astronomers to calculate what constellation the sun was in on the 15th of the month (the full moon) so they could calculate when an addition month was needed in the year to keep the actual and ideal years as aligned as closely as possible, lending credence to the idea that the Babylonians did this by calculation rather than observation prior to the Greek mathematicians.

By Thiagobf - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=45649439 Blue line: Earths orbit Grey line: Moon orbit Green line: Line of nodes Yellow line: Line to perigee Red lines: Velocity vectors Middle: (Camera follows Earth keeping Sun always behind it.) Demonstrates how the inclination of the moon's orbit precludes eclipses most of the time, leading to distinct eclipse seasons. Bottom left: (Camera follows Earth keeping its initial orientation, "Sun passes Earth" once per year .) Shows that the periodicity and recurrence of eclipses is governed by the Saros cycle, a period of approximately 6,585.3 days (18 years 11 days 8 hours). It was known to the Chaldeans as a period when lunar eclipses seem to repeat themselves, but the cycle is applicable to solar eclipses as well. Bottom right: View from the top shows how the moon orbital elements (argument of perigee PE and longitude of ascending node AN) change with time, returning to a similar configuration after one saros. One saros period after an eclipse, the Sun, Earth, and Moon return to approximately the same relative geometry, a near straight line, and a nearly identical eclipse will occur, in what is referred to as an eclipse cycle. (description from https://en.wikipedia.org/wiki/Saros_(astronomy)#/media/File:Saros15122015.gif

Babylonians also were able to calculate the cycle of lunar eclipses, which occur about every 5-6 months in an 18 year cycle of magnitude and duration (there are 38 eclipses in 18 years, and 33 of these are 6 months apart). Lunar eclipses are visible anywhere on the earth that it is night, making them more 'important' to the Babylonians, and their prediction would allow for preparation for those rituals. The distribution of five month time periods follows a pattern of 8 six month eclipses, a five month, follows by 7 six month, then 8, then 7, then 8 and then the pattern begins again (8 - 7 - 8 - 7 - 8). The Babylonians were definitely aware of this as early as 575 BCE and there appears to be document recording the lunar eclipse of 6 February 747 BCE noting this pattern. This is called the Saros cycle and is the basis by which we predict eclipses to this day, though our numbers have gotten more exact with our improved time keeping methods. We even number the Saros cycles to a lunar eclipse dated 23 February 1994 BCE.

By Susanne M Hoffmann - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=109209823

While we cannot know for sure exactly how people kept track of time prior to settled agriculture, we do know that once settled, study of the night sky and the timing of equinoxes and solstices were of great import, not just for keeping track of the cycles of sowing and harvesting of crops, but also for rituals, for protecting against bad omens, and even for planned days of rest. Even something as complex as the pattern of eclipses can be puzzled out over the course of many years and continue to affect the word, thousands of years later.

Resources

Standard Babylonian (Nippur-Babylonian) Calendar

Counting Days in Ancient Babylon: Eclipses, Omens, and Calendrics during the Old Babylonian Period (1750-1600 BCE)

[treeprince]

the problem with making commitments at the start of a new year on the western calendar is that its january and the vitamin D deficiency hasnt even begun to start chewing us down yet

[zmaragdos]

back on my bullshit

(drinking green tea by the liter)

[jlbugesq]

[waitinqroom]

2024 year of the dragon my ASS

[sunnyapollonjabrigidotter]

I think id need calendar stickers, lol.. & detachable kind, cs im messy af... ⏳️🪻☀️

[montereybayaquarium]

Happy Lunar New Year!

Tonight is the first new moon of the lunisolar calendar, a time for new beginnings. The moon plays an important role in our world’s ocean—from controlling the tides, to playing conductor in the orchestra of marine life cycles.

Moon jellies—named simply for their lunar satel-likeness—are delightfully drifting reminders of our nearest sea-lestial body. We hope that tonight you can find time to reflect in the shadow of the new moon and shellebrate new beginnings. 

Wishing you a year of prosperity! ♥️ 🌑 🧧

[seismologically-silly]

I got a plot bunny last night and I’m really excited about it but I can’t stop thinking about the calendar

[markrosewater]

happy rosh hashanah mark.

Thank you.

For my non-Jewish followers, Rosh Hashanah is the Jewish New Year. Jewish holidays follow a Hebrew (sometimes called a Jewish) Calendar which is a lunisolar calendar.

[sumerianlanguage]

Hi there! I’d like start with a thank you for taking the time and effort to help people who are interested in all things Sumerian learn! :D I’m not sure if this has been asked before, but what were the names given for the months of the year by the Sumerians? I’m curious as to how a lyric from a song like "Do you remember the 21st night of September" would translate into Sumerian

Hello, and thanks for the kind words!

The Sumerians used a system of twelve or thirteen lunisolar months, similar to other lunisolar calendars like the Hebrew calendar. (In fact, many Hebrew-calendar months derive their names from the Babylonian calendar, a later standardization of the Sumerian calendar months.) In most periods, the months started with the first visible crescent moon (right after the new moon) closest to the spring equinox; months could be anywhere from 28 to 30 days long, depending on when the next new crescent moon was sighted. The months would be:

Barazagngar 𒌚𒁈𒍠𒃻 (~March-April) Ezemgusisu 𒌚𒂡𒄞𒋛𒋢 (~April-May) Sigushubbangar 𒌚𒋞𒄷𒋛𒊒𒁀𒃻 (~May-June) Shunumun 𒌚𒋗𒆰 (~June-July) Neizingar 𒌚𒉈𒉈𒃻 (~July-August) KinInanna 𒌚𒆥𒀭𒈹 (~August-September) Duku 𒌚𒇯𒆬 (~September-October) Apindua 𒌚𒄑𒀳𒂃𒀀 (~October-November) Gan'gane 𒌚𒃶𒃶𒌓𒁺 (~November-December) Abe 𒌚𒀊𒌓𒁺 (~December-January) Ziza 𒌚𒍩𒀀 (~January-February) Shekinku 𒌚𒊺𒆥𒋻 (~February-March) Dirishekinku 𒌚𒋛𒀀𒊺𒆥𒋻 was the intercalary month, only included in some years, to keep the lunar months in line with the annual solar cycle

Note that each month had any of a wide variety of variant spellings, and the system above was pretty unstandardized until the later Babylonian era. The initial 𒌚 sign is the determiner for months and is unpronounced.

I'm having some trouble finding a consistent pattern for "on the #th day of [month name]", but the general way to say "on the #th day of the month" is ituda ud #(-kam), literally "in the month its #th day". Assuming we can slot in a month name, say Duku (the most likely month for late September to fall in), alongside ngi "night" and nishdish (my best guess for "21", whose pronunciation we don't know), then Dukua ngi nishdishakam would be "The 21st night of Duku".

Using one of the words for "remember", pad, you could say Zae Dukua ngi nishdishakam ibpaden? "Are you remembering [what happened] on the 21st night of Duku?" Though note that this would almost never correspond to our own September 21, for which you'd have to calculate the exact date for each year; I think for 2024 it'd be the 18th of Duku based on my quick counting, but it could fall anywhere from the end of KinInanna to the start of Apindua. I hope that's helpful!

[geoviki]

Chinese Holidays

I'm going to post about the special chapters in a minute, and that post is already too long, so I'm stuffing the background info about holidays in its own post. Complete with holiday picture!

These are Chinese holidays when the special chapters take place.

Chinese New Year, aka Lunar New Year or the Spring Festival, celebrates the beginning of a new year on the Chinese calendar. Marking the end of winter and the beginning of spring, this festival takes place from Chinese New Year's Eve (begins on the new moon between 21 January and 20 February) to the Lantern Festival, held on the 15th day of the year.  New Year's Eve is an occasion for Chinese families to gather for the annual reunion dinner.  Other activities include lighting firecrackers and giving money in red envelopes.  Note that this period may overlap with Valentine’s Day.

China has several Valentine's days to celebrate, including February 14th (western Valentine’s Day), 520/521 Day (an informal Chinese Internet Valentine’s Day on May 20/21), and the Qixi Festival. 

520/521 Day The number “520” phonetically resembles “Wo Ai Ni” or “I Love You” in Chinese.  "520" (May 20) for "I love you"; "521" (May 21) for "I am willing to accept your love."

The Qixi Festival (Chinese Valentine’s Day) celebrates the annual meeting of the cowherd and weaver girl in mythology. It falls on the 7th day of the 7th lunisolar month on the Chinese calendar (usually August).

Mid-Autumn Festival happens on the 15th day of the 8th month of the lunar calendar with a full moon at night (Sept-Oct). The moon is the biggest symbol of the harvest festival.  The Mid-Autumn Festival is all about reunion with family members.  Lanterns are carried and displayed.

Chinese National Day Begins 1 October, and another six days are added to the official holiday, making it a de facto public holiday also known as Golden Week. Festivities and concerts are held nationwide.

Dragon Boat Festival is a traditional Chinese holiday that occurs on the fifth day of the fifth month of the Chinese calendar, which corresponds to late May or early June.

Christmas Day in China is on December 25th each year. However, Christmas traditions in the country are relatively young, and it is mainly celebrated as a commercial season instead of a religious day.

[fei-ren-zai]

Employee card merch (selling on Douyin, Taobao, Tmall, and Xiaohongshu)

Source: FRZ Weibo

Note: Jingwei's birthday is the 27th day of the 7th month of the Chinese lunisolar calendar.