Sunday, October 9, 2022

What is Jewish Standard Time- All about the calendar


Jewish Time

Link to presentation: opens at 1:04 into the video of Oct 8


We are all on different time zones.

Yeke Time—10 minutes ahead.

Yemenite time- 15 minutes ahead.

Standard American Jewish- ½ hour late

Standard Israeli time- allow an hour till everyone is organized

Farsi Jewish time- never be the first one to show up at an event.

Chasidic time- when the Rebbe feels like it. Does God wear a watch?

Of course, we are all time obsessed, ever since we put clocks in those beautiful medieval towers.



Time is a universal topic- Stonehenge- in Britain- a system to mark the seasons.

Mayans, Aztecs- had own calendar systems- 2 systems, one, for agriculture,  ,365 day solar, the other a 260 day cycle for religious events- matched every 52 years.

Romans- The original calendar consisted of ten months beginning in spring with March; winter was left as an unassigned span of days. These months ran for 38 nundinal (nine day) cycles, each forming an eight-day week (nine days counted inclusively, hence the name) ended by religious rituals and a public market. -later, refined by Julius and Augustus Ceasars with 2 extra months, hence July, August. Then,  updated by Pope Gregory, to our current Western calendar.

Islam- pre-Islam, early Arabian calendars merged lunar and solar, but following Mohammed, solely lunar cycle, which is ten days shorter. Basically, then, religious dates move around, compared to the solar. Moslems states have adopted the Gregorian calendar for government and business purposes.


How have we measured our years?:

Here is our very first Jewish calendar: Gezer calendar

Gezer, 20 miles west of Jerusalem. It is commonly dated to the 10th century BCE.

The inscription, known as KAI 182, is in Phoenician or paleo-Hebrew script:



ירחואספ ירחוז

רע ירחולקש






אבי (ה)




yrḥw ʾsp/ yrḥw z

rʿ /yrḥw lqš

yrḥ /ʿṣd pšt

yrḥ qṣr šʿrm

yrḥ qṣrw kl

yrḥw zmr

yrḥ qṣ

ʾby [h]


Two months gathering (October, November — in the Hebrew calendar TishreiCheshvan)

Two months planting (December, January — KislevTevet)

Two months late sowing (February, March — ShvatAdar)

One month cutting flax (April — Nisan)

One month reaping barley (May — Iyar)

One month reaping and measuring grain (June — Sivan)

Two months pruning (July, August — TammuzAv)

One month summer fruit (September — Elul)

Abij [ah][9]


May have been a school child’s homework assignment-which means children in ancient Israel were being taught literacy! Abi-may be shirt for Abiyah-Yah is my father- oldest form of “ Yah” found. Yarcho- would later be vocalized as “ yarchei”-months of. Yarch- Yareach-month( moon). Connect to” O-reakh”-a visitor- travelling across the night sky.

( Please note- in my video, the source I used for the Gezer inscription had the name” Abij[ah] transcribed in reverse order. I have a better image of the actual tablet, which shows the letters written top to bottom. The student squeezed his name into the available space.)


We know of only 4 months with names:

·        Biblical- marking from Chodesh Haaviv ( of the Springtime) -using lunar sightings-Chodesh- from :Chadash” New- New Moon, Aviv – first month[4]

·        Ziv – second month[5]

·        Ethanim – seventh month[6] and

·        Bul – eighth month.[7]


Months , like days, have numbers, not names, as they are not associated with the gods!

Rishon, sheni-. Roman- not Janus, not Mars.

Why no names to days of week- associated with the planets, in turn, each planet , a god- Sun-day, Moon-day,Tuesday ( Ti) Wed(Wotan) Thurs( Thor) Friday-Friga-Sat-Saturn.

Months- Roman- not Janus, not Mars.


Why the disconnect? Probably an early concept that God creates time as well as space. Not only is space inside God, but time is also. Time and space are relative. Beat Einstein by a long shot.


Psalm 90:4 A thousand years in your sight     are like a day that has just gone by,
    or like a watch in the night. י אֶ֪לֶף שָׁנִ֡ים בְּֽעֵינֶ֗יךָ כְּי֣וֹם אֶ֭תְמוֹל כִּ֣י יַֽעֲבֹ֑ר וְאַשְׁמוּרָ֥ה בַלָּֽיְלָה׃

The “ ashmurah”_ night watch-a third of the night ,only!

Also, rejection of the power of heavenly forces that could operate independently. “ Ain Mazal leYisrael”

אִיתְּמַר, רַבִּי חֲנִינָא אוֹמֵר: מַזָּל מַחְכִּים, מַזָּל מַעֲשִׁיר, וְיֵשׁ מַזָּל לְיִשְׂרָאֵל. רַבִּי יוֹחָנָן אָמַר: אֵין מַזָּל לְיִשְׂרָאֵל. וְאַזְדָּא רַבִּי יוֹחָנָן לְטַעְמֵיהּ, דְּאָמַר רַבִּי יוֹחָנָן: מִנַּיִין שֶׁאֵין מַזָּל לְיִשְׂרָאֵל? שֶׁנֶּאֱמַר: ״כֹּה אָמַר ה׳ אֶל דֶּרֶךְ הַגּוֹיִם אַל תִּלְמָדוּ וּמֵאוֹתוֹת הַשָּׁמַיִם אַל תֵּחָתּוּ כִּי יֵחַתּוּ הַגּוֹיִם מֵהֵמָּה״ — הֵם יֵחַתּוּ, וְלֹא יִשְׂרָאֵל.

It was stated that Rabbi Ḥanina says: A constellation makes one wise and a constellation makes one wealthy, and there is a constellation for the Jewish people that influences them. Rabbi Yoḥanan said: There is no constellation for the Jewish people that influences them. The Jewish people are not subject to the influence of astrology. And Rabbi Yoḥanan follows his own reasoning, as Rabbi Yoḥanan said: From where is it derived that there is no constellation for the Jewish people? As it is stated: “Thus said the Lord: Learn not the way of the nations, and be not dismayed at the signs of heaven; for the nations are dismayed at them” (Jeremiah 10:2). The nations will be dismayed by them, but not the Jewish people.Talmud Shabbat 156 a


The basis for the calendar is then the month. Very practical- travel at night- use as a guide.The phases of the moon make it easy to track the days that pass. Psychological- it approximates a woman’s period. Rosh Chodesh- a half day festival for women. Depends on witness sightings to identify the first sliver for the New Moon/Month.

However, agriculture requires a different cycle- that of the sun.The festivals are dated from the new moon, the 1st sliver-Rosh Hashanah and Rosh Chodesh, but agricultural- the 15th-mid month, full moon, but it Pesach must be spring harvest, Shavuot must be the conclusion of that harvest time, sukkoth must be the fall harvest- these are solar events. So we have cycles that need to be coordinated. - but also, solar, to match seasons “tekufah.”



A moon-month- 28 , divide in half, 14 days, then half again, quarter moon, 7 days, Shabbat. 7 becomes a basic cycle for everything-matches the visible planetary objects-sun-moon-mercury, venus, mars ,Jupiter, Saturn,

It also includes a 7 day cycle, of the week-Shabbat, which is repeated in the two anchor festivals of the year- Pesach and Sukkoth. Seven months apart. Then, a 7 week cycle, Pesach to Shavuot. A 7 year cycle, Shmitah year, a 7 Shmittah cycle, and a separate year- Yovel- Jubilee ( from trumpet blast)-50 years total. Other uses of the 7 cycle-70 years ( Book of Daniel- 70 weeks- as a reference to 70 years- to deliverance.)

Sometime with the return from Babylonian captivity, we accept the Mesopotamian names of months and cycle from Tishrei( tekufat Hashanah), not Nisan( Aviv).same as we now accept Jan, Feb, etc

We now have multiple competing calendars among the children of Israel.

Samaritans- student tour to Shechem- Gerizim, Samaritan synagogue. They were all gathered, fasting- Yom Kippur, by their calculations, about a month after ours.Indeed, their calendar cycle is very similar, but runs one month behind.

Book of Jubilees-an “ external book”-( still preserved by Ethiopian Jews) used a 364 Day Solar Year c 150 BCE.

From Prof Michael Segal-about the book of Jubilees:

 Jubilees follows a solar calendar of 364 days per year, to which it refers as a “complete year” (שנה תמימה):

“Now you command the Israelites to keep the years in this number—364 days. Then the year will be complete and it will not disturb its time from its days or from its festivals because everything will happen in harmony with their testimony. They will neither omit a day nor disturb a festival. (6:32)

A similar calendar has been discovered in some of the Dead Sea scrolls from Qumran. A 364-day calendar is useful from the perspective that the number of days in a year is divisible by 7 (52 weeks = 364 days.13  months of 28 days each). Every date in the calendar is therefore anchored to a specific day of the week, and does not change from year to year.


In late Second Temple times (i.e., 1st century BCE to 70 CE), calendrical matters were regulated by the Sanhedrin, or council of elders, at Jerusalem. The testimony of two witnesses who had observed the new moon was ordinarily required to proclaim a new month.

Start counting from Rosh Hashanah- but it is in first of month-what if witnesses come late? Origin of 2 day Rosh Hashanah in Israel. Once, Rosh Hashanah is declared, the other holidays are fine. All of the land of Israel is maybe a fews day hike in any direction. However, how to announce dates of the festivals to Babylonia-hundreds of miles away? Signal flares-Masuot. Set by watchmen on a series of hilltops.

Mishna on Rosh Hashanah-

Initially, they would light torches on the mountaintops, from one peak to another, to signal to the community in Babylonia that the month had been sanctified. After the Samaritans [Kutim] corrupted and ruined this method by lighting torches at the wrong times to confuse the Jews, the Sages instituted that messengers should go out to the Diaspora and inform them of the start of the month.

With that, the communities outside of Israel added one day to each Festival, just in case the messengers would come late.Hence, inUS, 8 days Pesach, 2 day Shavuot, etc, but in Israel one 7, 1, etc.


Leap years were proclaimed by a council of three or more rabbis with the approval of the nasi, or patriarch, of the Sanhedrin.

The problem of Pesach- leap year-is added the month before Pesach, Adar. Adar I & Ii. depended at first on witness sightings of signs of spring. What if the witnesses were blocked from appearing? Pesach and Shavuot would be thrown off kilter.

What interference- fight between the eastern and western empires, and the bishop of Rome vs Bishop of Constantinople. 2 different approaches to calculating Easter- based on the start of Pesach. Both churches based themselves on Easter being after Pesach. Eretz Yisrael-under Eastern Empire. If Jewish court could not meet to announce Pesach, the other church could not know when to start Easter!

Jewish persecution under the Roman emperor Constantius II (reigned 337–361) and advances in astronomical science led to the gradual replacement of observation by calculation.


Finally, Palestinian patriarch Hillel II introduced a fixed and continuous calendar in 359 CE.

What is the result? This is for the mathematicians:(details from Wikipedia on Hebrew Calendar):

Leap years

The Jewish calendar is based on the Metonic cycle (when the lunar year meets up with the solar year ) of 19 years, of which 12 are common (non-leap) years of 12 months and 7 are leap years of 13 months. To determine whether a Jewish year is a leap year, one must find its position in the 19-year Metonic cycle.

This position is calculated by dividing the Jewish year number by 19 and finding the remainder. (Since there is no year 0, a remainder of 0 indicates that the year is year 19 of the cycle.) For example, the Jewish year 5783 divided by 19 results in a remainder of 7, indicating that it is year 7 of the Metonic cycle.[h]

Years 3, 6, 8, 11, 14, 17, and 19 of the Metonic cycle are leap years.

To assist in remembering this sequence, some people use the mnemonic Hebrew word GUCHADZaT גוחאדז״ט, where the Hebrew letters gimel-vav-het aleph-dalet-zayin-tet are used as Hebrew numerals equivalent to 3, 6, 8, 1, 4, 7, 9. The keviyah records whether the year is leap or common: פ for peshuta (פשוטה), meaning simple and indicating a common year, and מ indicating a leap year (me'uberetמעוברת).[88]

Another memory aid notes that intervals of the major scale   {
\override Score.TimeSignature #'stencil = ##f
\relative c' { 
  \clef treble \time 7/4
  c4 d e f g a b c
} } follow the same pattern as do Jewish leap years, with do corresponding to year 19 (or 0): a whole step in the scale corresponds to two common years between consecutive leap years, and a half step to one common year between two leap years. This connection with the major scale is more plain in the context of 19 equal temperament: counting the tonic as 0, the notes of the major scale in 19 equal temperament are numbers 0 (or 19), 3, 6, 8, 11, 14, 17, the same numbers as the leap years in the Hebrew calendar.


A simple rule for determining whether a year is a leap year has been given above. However, there is another rule which not only tells whether the year is leap but also gives the fraction of a month by which the calendar is behind the seasons, useful for agricultural purposes. To determine whether year n of the calendar is a leap year, find the remainder on dividing [(7 × n) + 1] by 19. If the remainder is 6 or less it is a leap year; if it is 7 or more it is not. For example, the remainder on dividing [(7 × 5783) + 1] by 19 is 12, so the year 5783 is not a leap year. The remainder on dividing [(7 × 5784) + 1] by 19 is 0, so the year 5784 is a leap year.[89] This works because as there are seven leap years in nineteen years the difference between the solar and lunar years increases by 7/19-month per year. When the difference goes above 18/19-month this signifies a leap year, and the difference is reduced by one month.


The Jewish Talmudic Calendar assumes that a month is uniformly of the length of an average synodic month,(lunar) taken as exactly 291375325920 days (about 29.530594 days, which is less than half a second from the modern scientific estimate); it also assumes that a tropical year is exactly 12719 times that, i.e., about 365.2468 days. Thus it overestimates the length of the tropical year (365.2422 days) by 0.0046 days (about 7 minutes) per year, or about one day in 216 years. This error is less than the Julian years (365.2500 days) make (0.0078 days/year, or one day in 128 years), but much more than what the Gregorian years (365.2425 days/year) make (0.0003 days/year, or one day in 3333 years).


In every 19 years, the solar and lunar calendars basically synchronize, with only about 2 hours of difference.


Thus each 19 years is called a "small mahzor" in the Jewish Talmudic calendar, which is equivalent to the Greek metonic cycle, although they do not start on the same year. The year of creation according to the Rabbinical Chronology (3761 BCE) is taken as year 1 in the first Small Mahzor. The Greek cycle begins from an arbitrary year, usually from the beginning of the Common Era (Anno Domini).


If every 13 Small Mahzor is called an Iggul, because 12 times 2 hours is a day, and 30 days are a month, then in less than 30 Igguls a whole intercalary( ibbur) month should be removed.

The position of the years in a small Mahzor is called the golden number. The pattern of the leap years change slightly in each Iggul, but the Jewish Talmudic calendar fixed the leap years in the year with golden numbers 3, 6, 8, 11, 14, 17, 19. If a Leap year marked L, and the Following year F, and the other common year as O, then


Golden numbers




















Year types





















There are other Tweeks in the system: some months 30, some, 29. Which depends on what part of the cycle, because:

 "לא אדו ראש

 (ראש השנה לא יחול בימים א, ד, ו) לא)

 לא בדו פסח" (פסח לא יחול בימים ב, ד, ו) "

1st Day Rosh hashanah cannot fall on Sunday, Weds, or Friday,( and so Yom Kippur will never fall on Friday or Sunday ( can’t  cook a proper meal to eat after the fast on Friday, can’t prepare a good meal for before the fast, and  Hoshanah Rabbah never on Shabbat , because you can’t break the willows, and 1st Day Pesach never on Monday, Weds, Friday, so that it is always the same number of days after Rosh H.

This is only the tip of the iceberg!

Year 5783 since the creation of the world,
according to the traditional count.

·        This year has 355 days,
making it a full (
שלמה) year.

·        In 5783, Rosh Hashanah is on Monday,
while Passover is on Thursday

According to the Machzor Katan, the 19-year (Metonic) cycle used to keep the Hebrew calendar aligned with the solar year:

·        This year is the 7th year of the 305th cycle.
It is not a leap year.

According to the Machzor Gadol, a 28-year solar cycle used to calculate the date to recite Birkat Hachama, a blessing on the sun:

·        This year is the 15th year of the 207th cycle.

According to the current reckoning of sabbatical (shmita) years:

·        This year is the 1st year of the cycle.

·        It is a maaser sheni year.







As a measure of global world events: The seven cycle on a scale of world history:

It is taught in a baraita in accordance with the opinion of Rav Ketina: Just as the Sabbatical Year abrogates debts once in seven years, so too, the world abrogates its typical existence for one thousand years in every seven thousand years, as it is stated: “And the Lord alone shall be exalted on that day

תנא דבי אליהו

 ששת אלפים שנה הוי עלמא שני אלפים תוהו שני אלפים תורה שני אלפים ימות המשיח The school of Eliyahu taught: Six thousand years is the duration of the world. Two thousand of the six thousand years are characterized by chaos; two thousand years are characterized by Torah, from the era of the Patriarchs until the end of the mishnaic period; and two thousand years are the period of the coming of the Messiah.Talmud Sanhedrin 97 a



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