Picture courtesy Wikimedia
Astronomical occurrences and calculations are important in determining Holy Days in many religious traditions.
Baha'i: Naw Ruz
http://www.cartage.org.lb/en/themes/sciences/astronomy/theuniverse/Timekeepingandthecelestial/Calendars/calages/variouscal/Others.htm#Anchor-4711
The Baha'i New Year's Day (Naw Ruz) falls on the Spring Equinox. This usually occurs on 21 March but if the Equinox falls after sunset on 21 March, Naw Ruz is to be celebrated on 22 March because the Baha'i day begins at sunset.
British/Celtic Ancient (also often celebrated by Wiccans)
http://www.crossquarter.net/
Crossquarter days were the markers of the changing seasons, and the solstices and equinoxes that we use now were then considered the midpoints of each season (hence midwinter's and midsummer's days). The crossquarter days are the halfway points between a solstice and equinox, if you see what I mean. A good series of articles outlining solar festivals in many different cultures can be found here under "Seasonal Markers". Meanwhile, here is a simple list of the Celtic seasonal holidays according to my current understanding:
Samhain (crossquarter day) - christianized as All Hallows' Eve/All Saints' Day, aka Halloween. Beginning of winter.
Yule - aka Midwinter's day - winter solstice. By the Roman calendar in use at the time Christmas became established, the winter solstice fell on December 25.
Imbolc (crossquarter day) - persists as Groundhog Day. First day of spring.
Ostara - spring equinox - Easter. Eggs and rabbits = fertility symbols.
Beltane (crossquarter day) - May Day. First day of summer.
Midsummer's day - summer solstice.
Lughnasad (crossquarter day) - christianized as Lammas, "loaf-mass" (first harvest), but now the least remembered of the four crossquarter days. Would be around the beginning of August. First day of autumn.
Autumn equinox.
Christian: Easter
http://aa.usno.navy.mil/faq/docs/easter.html
The usual statement, that Easter Day is the first Sunday after the full moon that occurs next after the vernal equinox, is not a precise statement of the actual ecclesiastical rules. The full moon involved is not the astronomical Full Moon but an ecclesiastical moon (determined from tables) that keeps, more or less, in step with the astronomical Moon.
The ecclesiastical rules are:
- Easter falls on the first Sunday following the first ecclesiastical full moon that occurs on or after the day of the vernal equinox;
- this particular ecclesiastical full moon is the 14th day of a tabular lunation (new moon); and
- the vernal equinox is fixed as March 21.
resulting in that Easter can never occur before March 22 or later than April 25. The Gregorian dates for the ecclesiastical full moon come from the Gregorian tables. Therefore, the civil date of Easter depends upon which tables - Gregorian or pre-Gregorian - are used. The western (Roman Catholic and Protestant) Christian churches use the Gregorian tables; many eastern (Orthodox) Christian churches use the older tables based on the Julian Calendar.
In a congress held in 1923, the eastern churches adopted a modified Gregorian Calendar and decided to set the date of Easter according to the astronomical Full Moon for the meridian of Jerusalem. However, a variety of practices remain among the eastern churches.
There are three major differences between the ecclesiastical system and the astronomical system.
- The times of the ecclesiastical full moons are not necessarily identical to the times of astronomical Full Moons. The ecclesiastical tables did not account for the full complexity of the lunar motion.
- The vernal equinox has a precise astronomical definition determined by the actual apparent motion of the Sun as seen from the Earth. It is the precise time at which the apparent ecliptic longitude of the Sun is zero. (Yes, the Sun's ecliptic longitude, not its declination, is used for the astronomical definition.) This precise time shifts within the civil calendar very slightly from year to year. In the ecclesiastical system the vernal equinox does not shift; it is fixed at March 21 regardless of the actual motion of the Sun.
- The date of Easter is a specific calendar date. Easter starts when that date starts for your local time zone. The vernal equinox occurs at a specific date and time all over the Earth at once.
Inevitably, then, the date of Easter occasionally differs from a date that depends on the astronomical Full Moon and vernal equinox. In some cases this difference may occur in some parts of the world and not in others because two dates separated by the International Date Line are always simultaneously in progress on the Earth.
For example, take the year 1962. In 1962, the astronomical Full Moon occurred on March 21, UT=7h 55m - about six hours after astronomical equinox. The ecclesiastical full moon (taken from the tables), however, occurred on March 20, before the fixed ecclesiastical equinox at March 21. In the astronomical case, the Full Moon followed its equinox; in the ecclesiastical case, it preceded its equinox. Following the rules, Easter, therefore, was not until the Sunday that followed the next ecclesiastical full moon (Wednesday, April 18) making Easter Sunday, April 22.
Similarly, in 1954 the first ecclesiastical full moon after March 21 fell on Saturday, April 17. Thus, Easter was Sunday, April 18. The astronomical equinox also occurred on March 21. The next astronomical Full Moon occurred on April 18 at UT=5h. So in some places in the world Easter was on the same Sunday as the astronomical Full Moon.
Egyptian Ancient: Coming of Sopdet.
http://phoenixqi.blogspot.com/2007/03/how-long-does-phoenix-live.html
The Egyptians had a calendar of 365 days; three seasons of 120 days each, and a 5-day period of feasting. The season that interests us is Akhet, the summer growing season. The first day of Akhet which, in 3000 BCE, was at the time of the Summer Solstice, heralded the yearly flooding of the Nile and meant the first day of the agricultural year, the growing season
There is another astronomical event which takes places at that time; the heliacal rising of Sirius, the star we call the Dog Star, one of the most important astronomical bodies to the ancient Egyptians. (A heliacal rising is the appearance of a star above the horizon just before the sun rises.)
While we, today, call Sirius the Dog star because it is the brightest star in the constellation of Canis Major, the Ancient Egyptians called it Sothis or Sopdet/Sepdet. Sopdet, sometimes identified with Isis, was a fertility goddess associated with the star Sirius and the agricultural year. When Sirius/Sothis/Sopdet became visible in the morning sky just before the sunrise, the sighting was celebrated with a festival called "The Coming of Sopdet" because it was the time of year for the waters of the Nile to rise; she brought with her the waters that would bring fertility to the land.
Hindu & Sikh: Karwa Chauth festival
http://en.wikipedia.org/wiki/Karwa_Chauth
Karwa Chauth is a traditional Hindu festival and also a Sikh Festivals for married women (Suhagans), and is celebrated in some parts of India. Married women fast one whole day without food or water for the long life of their husbands. The ritual signifies extreme love and devotion to the husband, as evidenced by the wife's willingness to suffer for his well being.
It is celebrated on the fourth night after the full Moon in the month of kartik in the Hindu calendar. Karwa means clay pot and chauth means fourth night after the full moon. It has great social and cultural significance and is mostly practiced in northern India. Wives start their fast at night just after the appearance of the moon, within sight of their husbands. They then wait until the next night's moonrise to begin the fast breaking ceremonies, without consuming any food or drink. In the evening women dress in their best clothing, and adorn themselves with jewellery and henna. On sighting the moon, they look and offer prayers and worship to it, and then receive their first bite of food and water from their husbands. Thereafter, women consume their special meal prepared for the occasion.
Worshipping the moon involves filling up the karwa with specially prepared food and jewellery and offering it to the god. Karwas are also exchanged with other women after that. Further practices involve telling and listening to stories regarding origin of Karwa Chauth.
There are variations within regions, groups, and communities in India about rituals of starting and breaking the fast, and worshipping the moon. In Punjab, for example, women start their fast by consuming food called sergi sent or given by her mother-in-law before the dawn. The fast breaking ceremony involves looking at the moon through a sieve, and then looking at her husband's face. They often close their eyes in the process and do not see anyone but their husbands just after seeing the moon. In other parts of India, there is no provision of sergi.
Jainist and Hindu
http://en.wikipedia.org/wiki/Ekadasi
Ekadasi is the eleventh lunar day (Tithi) of the shukla (bright) or krishna (dark) paksha (fortnight) respectively, of every lunar month in the Hindu calendar (Panchang). In Hinduism and Jainism, it is considered spiritually beneficial day. Scriptures recommend to observe an (ideally waterless) fast from sunset on the day prior to ekadasi until 48 minutes after sunrise on the day following ekadasi.
Meaning of Ekadasi
Ekadasi is a Sanskrit word, which means 'the eleventh'. It refers to the eleventh day of a fortnight belonging to a lunar month. There are two fortnights in a lunar month—the bright and the dark. So, Ekadasi occurs twice in a month, in the bright fortnight and the dark fortnight.
The special feature of Ekadasi, as most people know it, is a fast, abstinence from food. This is how it is usually understood. In fact, the fast is only a practical expression and a symbol of something else that we are expected to do, which is of special significance to our personality.
Astronomy and astrology
We belong to the solar system — a huge family of which the sun is the head and the planets are the members. The sun guides the activities of this family including us. We are involved in the laws operating in this system. This is used in astrology. Astronomy studies the movements of planets and stars and astrology the effects on the contents of the system. The Ekadasi observance is an astrological phenomenon and it is observed due to this relation we have with some of the planets in the system. Ultimately to assist in purifying our consciousness to assist in re-establishing our awareness of the creator of the solar system By fasting one gives chance to give rest to the digest system, instead of regular heavy meals three times a day more fruits & light food is consumed by doing so person goes more for spiritual life moreover have better control over body & mind biggest gain is keeping healthy. Giving rest to intestine.
Jewish: Rosh Hashanah
http://en.wikipedia.org/wiki/Hebrew_calendar
Special holiday rules
| Day of Week | Number of Days |
| Monday | 353 | 355 | 383 | 385 |
| Tuesday | 354 |
|
| 384 |
| Thursday | 354 | 355 | 383 | 385 |
| Saturday | 353 | 355 | 383 | 385 |
Although simple math would calculate 21 patterns for calendar years, there are other limitations which mean that Rosh Hashanah may only occur on Mondays, Tuesdays, Thursdays, and Saturdays (the "four gates"), according to the following table:
The lengths are described in the section Names and lengths of the months.
In leap years, a 30 day month called Adar I is inserted immediately after the month of Shevat, and the regular 29 day month of Adar is called Adar II. This is done to ensure that the months of the Jewish calendar always fall in roughly the same seasons of the solar year, and in particular that Nisan is always in spring. Whether either Chesvan or Kislev both have 29 days, or both have 30 days, or one has 29 days and the other 30 days depends upon the number of days needed in each year. Thus a leap year of 13 months has an average length of 383½ days, so for this reason alone sometimes a leap year needs 383 and sometimes 384 days. Additionally, adjustments are needed to ensure certain holy days and festivals do or do not fall on certain days of the week in the coming year. For example, Yom Kippur, on which no work can be done, can never fall on Friday (the day prior to the Sabbath), to avoid having two consecutive days on which no work can be done. Thus some flexibility has been built in.
The 265 days from the first day of the 29 day month of Adar (i.e. the twelfth month, but the thirteenth month, Adar II, in leap years) and ending with the 29th day of Heshvan forms a fixed length period that has all of the festivals specified in the Bible, such as Pesach (Nisan 15), Shavuot (Sivan 6), Rosh Hashana (Tishri 1), Yom Kippur (Tishri 10), Sukkot (Tishri 15), and Shemini Atzeret (Tishri 22).
The festival period from Pesach up to and including Shemini Atzeret is exactly 185 days long. The time from the traditional day of the vernal equinox up to and including the traditional day of the autumnal equinox is also exactly 185 days long. This has caused some unfounded speculation that Pesach should be March 21, and Shemini Atzeret should be September 21, which are the traditional days for the equinoxes. Just as the Hebrew day starts at sunset, the Hebrew year starts in the Autumn (Rosh Hashanah), although the mismatch of solar and lunar years will eventually move it to another season if the modern fixed calendar isn't moved back to its original form of being judged by the Sanhedrin (which requires the Beit Hamikdash)
Karaite interpretation
Karaites use the lunar month and the solar year, but the Karaite calendar differs from the Rabbinical calendar in a few ways: Determination of the first month of the year - (called aviv), which is the month Passover falls out and determination of the first day of each month (Rosh Chodesh).
The 4 rules of postponement are not applied, as they are not found in the Tanakh. It is determined when to add a 13th month by observing the ripening of barley (called abib) in Israel, rather than the calculated and fixed calendar of Rabbinic Judaism. This puts Karaites in sync with the Written Torah, while other Jews are often a month later.
The beginning of each month is determined by the Rosh Chodesh - which can be calculated, but is confirmed by observation of the first sightings of the new moon in Israel.
For several centuries, many Karaites, especially those outside Israel, have just followed the calculated dates of the Oral Law (the Mishnah and the Talmud) with other Jews for the sake of simplicity. However, in recent years most Karaites have chosen to again follow the Written Torah practice.
Muslim: Ramadan
http://en.wikipedia.org/wiki/Ramadan_%28calendar_month%29
Ramadan or Ramadhan is the ninth month of the Islamic calendar and the holiest month in Islam.
The word Ramadan is derived from the word ramd "to burn". The entire month is spent fasting from dawn to dusk. The name came from the time before the Islamic calendar, when the month of Ramadan fell in the summer. Fasting during this month is often thought to figuratively burn away all sins. Muslims believe that the Qur'an was sent down to the earth during this month. Furthermore, Muhammad told his followers that the gates of Heaven would be open all the month and the gates of Hell would be closed. The first day of the next month is spent in great celebrations and rejoicings and is observed as the ‘Festival of Breaking Fast’ or `Eid ul-Fitr.
Timing
The Islamic calendar is a lunar calendar, and months begin when the first crescent of a new moon is sighted. Since the Islamic lunar calendar year is 11 to 12 days shorter than the solar year, Ramadan migrates throughout the seasons. The actual and estimated start and end dates for Ramadan in 2005-2008 were and are as follows:
Fasting in the month of Ramadan is one of the five pillars of Islam. Most Muslims insist on the local physical sighting of the moon to mark the beginning of Ramadan, but some insist on using the calculated time of the new moon or the Saudi Arabian declaration to determine the start of the month. As a result, Ramadan dates vary in different countries, but usually only by a day or two.
Native American: Vernal Equinox – Lakota
http://www.kstrom.net/isk/stars/starkno3.html
The Lakota were nomadic and didn't always camp at the same spots. The angle of direction and length of the sun's noon shadow can be determined, and provides a simple way to identify these 4 key days that mark the earth's seasons. There are painted hides usually identified in museums as "war bonnet" or "feather circles". These resemble elaborate compass roses used by mariners, and would be handy and portable for making solar shadow time measurements, if a stick with a plumb-bob (an arrowhead, say) were placed upright in the center of the pattern.
Of course there are stars in the sky in daytime; we can't see them because of the sun. This brings us to where we can explain timing of the start of the Lakota sacred spring ceremonial round. It begins, the elders say, when the sun enters the Lakota constellation Dried Willow. This includes Triangulum (which isn't too bright) and the brighter stars in Aries, the Ram. This was traditional in Western ancient astronomy too; spring, the vernal equinox, began when the sun was in Aries, and that was the start of the astronomical year for star-watchers. An easy way to tell when this has happened is by the first-magnitude star Antares ("the opposite of Aries").
So early evening rising just south of the ecliptic (sunpath horizon point) of first magnitude Antares (I don't know its Lakota name) indicates the sun has entered the Dried Willow constellation. Some time ago, this happened around March 20-21, the spring equinox, and was the signal for the Pipe Ceremony at winter camps that heralded a ceremonial round in the Black Hills, ending with a Solstice Sun Dance at Devil's Tower, (Grey Buffalo Horn) when the sun entered the Bear's Tipi constellation (part of Gemini) that represents it.
Now, though, everything in the skies happens about a month later than when these ancient observational calendars -- Egyptian, Mesopotamian, Chinese, as well as Lakota -- were drawn up. This happens because the earth's north-south axis revolves around the center of the earth, so the poles slowly sweep out 2 cones in the sky, joined at their tips in the earth's center. This cycle is called the precession of the equinoxes or precessional cycle. (Its cause is a gyroscopic effect of the moon's gravitational attraction to the earth's tidal bulge.) It takes about 26,000 years for one complete revolution to sweep out the double cone. During this time, the pole star changes, to whatever stars lie on the circle swept by the north-pointing end of the earth's axis. The Pole Star -- Wichahpi Owanjila, star that always stands in one place -- was Thuban (Alpha Draconis) in 3000 B.C. Around 7500 AD, Alpha Ceiphei will be the pole star, then Deneb, then bright Vega (14000 AD), then it'll swing around to Thuban again. For many centuries there has been and will be no bright star close enogh to where the pole is to serve as pole star; the bright northern stars and constellations then seem to revolve through the night about an empty center.
Shinto: Winter Solstice
http://www.gaiamind.org/moremoon.html
In the Japanese Shinto calendar this day is sacred to the Sun Goddess Amataseru-no-Mikuni, heroine of one of the world's great and typical festivals of the retreat and return of the Sun. When her brother, the raucous storm god and trickster Susanoo-no-Mikuni, insulted and ridiculed her, she withdrew into a cave and caused Earth to suffer in cold and darkness until other gods gathered to sing and dance outside Amaterasu's cave until they charmed her back out. Among the universal symbolisms of such stories is the principle that light avoids wild and violent action, and can tame it only by limiting it in patterns of order, symbolized by the music and the dance.
Sikh: see Hindu above
Sumerian: Moon phases
http://www.jameswbell.com/a005calendar.html
Holy days, time off from work, were usually celebrated on the first, seventh and fifteenth of each month. [i.e. New Moon, First Quarter Moon, and Full Moon] In addition to these holy days, there were also feast days which varied from city to city.
Wiccan: see British/Celtic Ancient above.
