Calendar

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Calendar

• Why do we use calendars?• Celebrate holidays – commandment from G_od

• To get ready for the coming seasons

• Helps to make plans

• More…

http://en.wikipedia.org/wiki/Hebrew_calendar

When is Rosh Hashanah evening?• The 29th of Elul

Convert your birth date to the Jewish calendar

•http://www.hebcal.com/converter

1st of Tishrei, 5772 = Thu, 29 September 2011

Moon’s Phase - US Navy Web Site!

http://tycho.usno.navy.mil/vphase.html

Hebrew Calendar

• Combination of Solar calendar and Lunar calendar

• The Jewish year is based on the

earth movement around the sun• The Jewish month is based on the

moon movement around the earth

But Why? Why do we use the combination of Lunar and Solar Calendars (or the Lunisolar Calendar)?

ש   א• ת-ח@ד< מור, א< Gשח, Hס יתG פ< Lש Gע Oיב, ו Lאב Gה

ש ח@ד< Oי ב Lיך:  כ לה< Xה א Gיהו Hלה Gהו Oך י Zיא Lיב, הוצ Lאב Gה

ה Gל Oי Gים--ל Hר Oצ Lמ Lיך מ לה< Xא .

• 1 Observe the month of Abib (the spring D.N.), and keep the passover unto the LORD thy God; for in the month of Abib the LORD thy God brought thee forth out of Egypt by

night.

http://www.mechon-mamre.org/p/pt/pt0516.htm

Step oneOnly the Solar Calendar will allow for us keep G_od’s commandment to have Passover during the spring.

Deuteronomy Chapter 16 ים Lר Gב Oד

STEP TWOThe months depend on the cycle of the moon. Our sages understood it from

the word “This” in the flowing quote:Exodus Chapter 12 מות Oש

ה ל-מ@ש< ה א< Gהו Oר י י@אמ< Hא  וים Hר Oצ Lץ מ ר< א< Oר@ן, ב Zל-אה א< Oו

אמ@ר. mל

ש ח@ד< Hהב  ה ז< Hם, ר@אש ה כ< Gל

ם, כ< Gאשון הוא ל Lים:  ר Lש Gד qחה. Gנ Gש Hי ה mש Oד Gח Oל

1 And the LORD spoke unto Moses and Aaron in the land of Egypt, saying:

2 This month shall be unto

you the beginning of months; it shall be the first month of the

year to you.

http://tora.us.fm/tnk1/tora/jmot/jm-12-02.html

• Time and place are two fundamental coordinates of life, and, in particular, of Jewish life and teaching. As regards "place," the Torah focuses on the Holy Land, the site of the Temple and the sacred City of Jerusalem, as the spiritual center for the Jewish people. One can also think of the Jewish home and of the synagogue as examples of places where there is something special, a quality of holiness.

• In the account of the Exodus there is another fundamental idea: the sanctification of time. This is expressed in the Divine instruction to Moses and the Jewish people that "This month shall be for you the first of the months, it will be the first month of the year." The Sages understand this as the law to sanctify the New Moon every month, and to calculate the details of the Jewish calendar.

• A key element in celebrating Passover and indeed any Jewish festival is the concept of the Jewish calendar. This runs as a lunar calendar, in which the months follow the phases of the moon. But the Jewish calendar also has to take into account the solar year, in order that Passover, in the first month, will always fall in the spring. Hence in a leap year, an extra month is added to the Jewish year.

• In ancient times witnesses who had seen the New Moon would come to the Law Court in Jerusalem, and there the Sages would proclaim the start of the new month. In later generations this became difficult on account of Roman persecution. The sage Hillel II (4th century CE) therefore calculated the details of the Jewish calendar and today the entire Jewish people around the world follow his system.

• The command to sanctify the New Moon and calculate the Jewish calendar was the first command given to the Jewish people as a whole. Rashi even suggests that this command might have been the beginning of the entire Torah.

• Through the calendar the Jewish people sanctify and transform time. Shabbat comes automatically every seven days; but the Jewish calendar, put in the hands of the leaders of the Jewish people, determines which day is the New Moon, and therefore which days are Festivals.

http://www.chabad.org/parshah/article_cdo/aid/823789/jewish/Sanctifying-Time.htm

http://www.daat.ac.il/daat/shabat/luach/month3.html

Problem !

• For the moon to go around the earth it takes 29.5 days

• 12 months in a year• 12*29.5=354 days in a lunar year• The Solar year has 365 days!• 365-354=11

• Eleven days are “missing”• How is this problem solved?

Solution !

• Add a lunar month every 2-3 years in the Jewish Calendar

• This year is called: Shana Meuberth = leap year

• Every 19 years there are 7 leap years

• Let’s do some math….

How many days are in19 years?

• Jewish year• Given:

– 29.5 days a month– 12 month a year– 7 times add a month in

19 years

• 29.5*12*19=6726• 29.5*7= 206.5• Total 6932.5 days in

19 years

• Solar year• Given:

– 365 days in a solar year

• 365*19=6935

• Total 6935 days in 19 years

Not 100% solution but not so bad

• Types of Years

• A year in the Hebrew calendar is normally twelve months: Tishrei, Cheshvan, Kislev, Tevet, Sh'vat, Adar, Nisan, Iyar, Sivan, Tammuz, Av, and Elul. An extra month (Adar is replaced with Adar I and Adar II) is intercalated in seven of every nineteen years (years 3, 6, 8, 11, 14, 17, and 19). Every 19-year cycle thus contains 235 months. These two cycles of years and months are so close that they diverge at the rate of only 4.5 days every 1000 years.

• Because a lunar month is not a whole number of days, the length of the months can be either 29 or 30 days. A typical year alternates 30- and 29-day months, beginning with Tishrei, which is 30 days. In leap years, Adar I is 30 days and Adar II is 29 days. To further bring the calendar into alignment with the lunar cycle, a year may need to be shortened or lengthened by one day: Kislev may be shortened to 29 days, or Cheshvan may be lengthened to 30 days. Thus, there are six types of years:

• Defective common years, with 353 days • Regular common years, with 354 days • Excessive common years, with 355 days • Defective leap years, with 383 days • Regular leap years, with 384 days • Excessive leap years, with 385 days

http://www.shirhadash.org/calendar/abouthcal.html

• Time and place are two fundamental coordinates of life, and, in particular, of Jewish life and teaching. As regards "place," the Torah focuses on the Holy Land, the site of the Temple and the sacred City of Jerusalem, as the spiritual center for the Jewish people and the world. One can also think of the Jewish home and of the synagogue as examples of places where there is something special, a quality of holiness.

• In the account of the Exodus there is another fundamental idea: the sanctification of time. This is expressed in the Divine instruction to Moses and the Jewish people that "This month shall be for you the first of the months, it will be the first month of the year." The Sages understand this as the law to sanctify the New Moon every month, and to calculate the details of the Jewish calendar.

• A key element in celebrating Passover and indeed any Jewish festival is the concept of the Jewish calendar. This runs as a lunar calendar, in which the months follow the phases of the moon. But the Jewish calendar also has to take into account the solar year, in order that Passover, in the first month, will always fall in the spring. Hence in a leap year, an extra month is added to the Jewish year.

• In ancient times witnesses who had seen the New Moon would come to the Law Court in Jerusalem, and there the Sages would proclaim the start of the new month. In later generations this became difficult on account of Roman persecution. The sage Hillel II (4th century CE) therefore calculated the details of the Jewish calendar and today the entire Jewish people around the world follow his system.

• The command to sanctify the New Moon and calculate the Jewish calendar was the first command given to the Jewish people as a whole. Rashi even suggests that this command might have been the beginning of the entire Torah.

• Through the calendar the Jewish people sanctify and transform time. Shabbat comes automatically every seven days; but the Jewish calendar, put in the hands of the leaders of the Jewish people, determines which day is the New Moon, and therefore which days are Festivals.

http://www.chabad.org/parshah/article_cdo/aid/823789/jewish/Sanctifying-Time.htm

מסכת ראש השנה דף כה עמוד א

http://daf-yomi.com/Dafyomi_Page.aspx?vt=1&massechet=291&amud=49&fs=0

http://he.wikisource.org/wiki/%D7%A8%D7%90%D7%A9_%D7%94%D7%A9%D7%A0%D7%94_%D7%9B%D7%94_%D7%90

רבן גמליאל[ כך מקובלני מבית [אמר להם ר"ג •אבי אבא אין חדושה של לבנה פחותה

מעשרים ותשעה יום ומחצה ושני שלישי שעה וע"ג חלקים

Synodic Month = New moon to new moon

Helek

• The helek (Hebrew חלק, meaning "portion", plural halakim חלקים) is a unit of time used in the calculation of the Hebrew calendar. The hour is divided into 1080 halakim. A helek is 31/3 seconds or 1/18 minute.

http://en.wikipedia.org/wiki/Helek

אין חדושה של לבנה פחותה מעשרים ותשעה יום ומחצה ושני שלישי שעה וע"ג חלקים

ימים29•

חצי יום•

שעה2/3•

חלקים73•

Not/less than/from

ימים29•

חצי יום•

שעה2/3•

חלקים73•

+

+

+

Time Unit

29 Day

0.5 Day

Total 29.5 days

2/3 of an hour Hour

73 Halakim Hour

1 Hour = 1080 Halakim

Time Unit

2/3*1080= 720 Halakim Hour

73 Halakim Hour

Total 793 Halakim Hour

Transfer units from Hour to Day

793/1080/24= 0.030594 Day

Total

Not less 29.5+ 0.030594 = 29.530594 Days

• The average length of the synodic* month is:

• Gmarah: 29.530594 days• NASA: 29.530589 days • From Britannica: 29.530588 days• Error: 1 day after about 16 millennia

*Synodic Month = New moon to new moon

•http://en.wikipedia.org/wiki/Lunar_month•http://eclipse.gsfc.nasa.gov/SEsaros/SEsaros.html•http://www.britannica.com/EBchecked/topic/578490/synodic-month

http://chem.ch.huji.ac.il/nmr/foo/ppt/nmoon_files/frame.htm

In my computer

Lunisolar calendar

• The Hebrew, Buddhist, Hellenic, Hindu lunisolar, Burmese, Tibetan, Chinese, Vietnamese, Mongolian, and Korean calendars are all lunisolar.

http://en.wikipedia.org/wiki/Lunisolar_calendar