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TABLE OF CONTENTS
Calendar
history
Leap months
The Jewish Months and
their Special Dates
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Jewish Month
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Approximate Secular Date
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This Month’s Special Dates
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Nissan
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March–April
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Passover
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Iyar
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April–May
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Lag B’Omer
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Sivan
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May–June
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Shavuot
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Tammuz
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June–July
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Menachem Av
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July–August
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Tisha B’Av
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Elul
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August–September
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Tishrei
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September–October
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The High Holidays (Rosh Hashanah and Yom Kippur), Sukkot, Shmini Atzeret, and Simchat Torah
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Marcheshvan
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October–November
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Kislev
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November–December
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Chanukah
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Tevet
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December–January
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Conclusion of Chanukah
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Shevat
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January–February
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Tu B’Shvat
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Adar
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February–March
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Purim
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The Gregorian calendar improves
the approximation made by the Julian calendar
by skipping three Julian leap days in every 400 years, giving an average year
of 365.2425 mean solar days long,[38] which has an error of about one day per 3300 years
with respect to the mean tropical year
(which translates to a calendar year that averages about 26 seconds longer than
the true length of the tropical year) , which in 2000 had a length of 365.24219
days (each day consisting of 86,400 SI
seconds)[39] but less than
half this error with respect to the vernal equinox year of 365.24237 days, and with respect to both solstices
the Gregorian Calendar gives an average year length that is actually shorter
than the true length. By any criterion, the Gregorian calendar is substantially
more accurate than the one day in 128 years error of the Julian calendar
(average year 365.25 days).
The Julian
calendar, a reform of the Roman calendar,
was introduced by Julius Caesar in 46 BC,
and came into force in 45 BC (709 ab urbe condita). It was chosen after consultation with the
astronomer Sosigenes of Alexandria and
was probably designed to approximate the tropical year, known at least since Hipparchus. It has a regular year of 365 days divided into 12
months, and a leap day is added to
February every four years. Hence the Julian year is on average 365.25 days
long.
The original
Roman calendar is believed to
have been a lunar calendar,[1] which may have been based on one of the Greek
lunar calendars. As the time between new moons
averages 29.5 days, its months would have been either hollow (29 days) or full
(30 days). Full months were considered powerful and therefore auspicious;
hollow months were unlucky. Unlike currently used dates, which are numbered
sequentially from the beginning of the month, the Romans counted backwards from
three fixed points: the Nones, the Ides and the Kalends of
the following month. This system originated in the practice of
"calling" the new month when the lunar crescent was first observed in the west after sunset. From the
shape and orientation of the new moon, the number of days remaining to the
nones would be proclaimed.
Roman
writers claimed that their calendar was invented by Romulus, the founder of Rome around 753 BC. His version contained ten months with the vernal equinox in the first month. However, his months were not lunar:
The calendar year
lasted 304 days and there were about 61 days of winter which were not assigned
to any month.[2] The later
months were named based on their position in the calendar: Quintilis
comes from quinque (meaning five), Sextilis from sex
(meaning six), September from septem (meaning seven),
October from octo (meaning eight), November from novem
(meaning nine) and December from decem (meaning ten).
Numa Pompilius, the
second of the seven traditional kings of Rome,
reformed the calendar of Romulus by
adding January and February around 713 BC
to the original ten months, although Quintilis, Sextilis, September, October,
November and December no longer agreed with their position in his calendar.
Although Numa wanted to have a lunar year of 354 days, Romans considered odd
numbers to be lucky and even numbers unlucky, so Numa added 51 days to the 304
days in the calendar of Romulus and took one day from each of the six 30-day
months giving a total of 57 days to share between January and February. January
was given 29 days leaving February with the unlucky number of 28 days, suitable
for the month of purification. Of the eleven months with an odd number of days,
four had 31 days each and seven had 29 days each.
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From a very
early time, the ancient Egyptians had a form of calendar based upon the
phases of the moon followed a calendar system of 360 days, with three
seasons, each made up of 4 months, with thirty days in each month. The
seasons of the Egyptians corresponded with the cycles of the Nile, and were
known as Inundation (pronounced akhet which lasted from June 21st to
October 21st), Emergence (pronounced proyet which lasted from October
21st to February 21st), and Summer (pronounced shomu which lasted from
February 21st to June 21st).
The beginning
of the year, also called "the opening of the year", was marked by
the emergence of the star Sirius, in the constellation of Canis Major. The
constellation emerged roughly on June 21st., and was called "the going
up of the goddess Sothis". The star was visible just before sunrise, and
is still one of the brightest stars in the sky, located to the lower left of
Orion and taking the form of the dogs nose in the constellation Canis Major.
Though the
Egyptians did have a 360 day calendar, in a literal sense they did have a 365
day calendar system. The beginning of the year was marked by the addition of
five additional days, known as "the yearly five days". These
additional five days, were times of great feasting and celebration for the
Egyptians, and it was not uncommon for the Egyptians to rituals, and other
celebratory dealings on these days. As they made no provision for a leap
year, the calendar and the seasons drifted out of step, and by the end of the
Old Kingdom there was a discrepancy of five months
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CALENDAR HISTORY.htm
July 29, 2017