When did all

Rosh Hashannah's beginning on September 11 first become the start ofHebrew leap years?ONLY

The last Rosh Hashannah to coincide with the Gregorian date September 11 will begin on Tuesday 7142H (3381g).

Until then, all of the Rosh Hashannah's coinciding with the Gregorian date September 11 will mark the start of a Hebrew leap year.

The first time that a Hebrew leap year began on the Gregorian date of September 11 was Rosh Hashannah 4511H (750g).

But it wasn't until **Rosh Hashannah 4614H (853g)** that ** ONLY**
Hebrew leap years could begin on the Gregorian date of September 11.

The Saturday which immediately precedes the observance of Rosh Hodesh
is known as

** Shabbat M'Vorchim**. On that particular Shabbat,
during the synagogue services, it is customary to announce not only the
coming of the new month, but also the specific time of the new month's molad.

Can the time of a

moladprecede theShabbat M'Vorchimon which it is to be announced?

**YES!**

The Saturday which immediately precedes the observance of Rosh Hodesh
is known as

** Shabbat M'Vorchim**. On that particular Shabbat,
during the synagogue services, it is customary to announce not only the
coming of the new month, but also the specific time of the new month's molad.

Correspondent **Larry Padwa** guessed at the correct answer based
on the following opinion:-

I'm guessing on this one.

I believe that the answer is yes.

If Rosh Hashannah is postponed by two days from the Molad of Tishrei (because of the

), then the remaining months of the year are likely to begin a day or two following their Molad.DehiyyotIt should therefore be possible for a Rosh Hodesh which falls on a Sunday to have its Molad on the previous Friday (two days earlier). In this event, the Shabbat M'vorchim would refer to a Molad on the preceding day.

Thank you **Larry Padwa** for your response, which leads to the next
question.

Is it nececessary that

Rosh Hashannahbe postponed so as to have amoladprecede theShabbat M'Vorchimon which its month is announced?

**NO!**

The Saturday which immediately precedes the observance of Rosh Hodesh
is known as

** Shabbat M'Vorchim**. On that particular Shabbat,
during the synagogue services, it is customary to announce not only the
coming of the new month, but also the specific time of the new month's molad.

A molad can precede the Shabbat M'Vorchim on which its month is announced even though Rosh Hashannah is not postponed for that year. This particular phenomenon occurs in 1.18% of all the Hebrew years.

The most recent molad to occur prior to Shabbat M'Vorchim for a year in
which Rosh Hashannah was not postponed was the molad of **Sivan 5689H
(Fri 7 Jun 1929g)**.

That molad arrived at 6d 19h 724p.

Rosh Hashannah5760H will begin onShabbat11 September 1999g.The

molad of Tishrei5760H is 6d 21h 801p, making thatmoladshy of aShabbatarrival by 2h 279p.The year 5760H will be a leap year consisting of 385 days. As a result, the following year 5761H will also begin on

Shabbat!What are at least 2 other Hebrew calendar phenomenae that will take place in the year 5760H?

** 1.** Although it is the

** 2.** The new year 5760H is also the

of which

** 3.** The

When next will 5 consecutive Hebrew years have 4

Rosh Hashannah's begin onShabbat?

The next pattern of of 5 consecutive Hebrew years in which 4 out of 5 begin
on Shabbat will not occur until **Rosh Hashannah 5936H
(Saturday 16 Sep 2175g)**.

The 5 Rosh Hashannah's are

5936H corresponding to Sat 16 Sep 2175g 5937H Sat 5 Oct 2176g 5938H Tue 23 Sep 2177g 5939H Sat 12 Sep 2178g 5940H Sat 2 Oct 2179g

Correspondent **Winfried Gerum** sent the following correct answer:

The next period with 4 out of 5 years beginning on Shabbat are the years 5936 through 5940.Three consecutive years cannot all commence on Shabbat. Therefore, periods with 4 out of 5 years starting on Shabbat must have their 3rd year starting on some day other than Shabbat.

Thank you very much **Winfried Gerum** for sharing these observations
with us.

Correspondent **Larry Padwa** also sent the following correct answer:

The next occurence of this will be in about 175 years. RH 5936 (Saturday 16-September 2175G) begins the next cycle.

Correspondent **Dwight D. Blevins** also noted that 247 years separated
the last such occurrence from the next one.

[Nearest to 5760H] When will 4 out of 5 consecutive

Yom Kippur's be observed onShabbat?

These are the nearest 5 consecutive Yom Kippur's in which 4 are to be observed on Shabbat:-

5771H corresponding to Sat 18 Sep 2010g 5772H Sat 8 Oct 2011g 5773H Wed 26 Sep 2012g 5774H Sat 14 Sep 2013g 5775H Sat 4 Oct 2014g

It is to be noted that **Yom Kippur 5774H (2013g)** will be observed on
**the earliest possible Gregorian date** now available to the holiday.

In the full Hebrew calendar cycle of 689472 years, which

molad of Tishreiwill be the first to be repeated as amolad of Tishrei?

The time of any molad is usually given as day, hour, minute and part.

There are 24*60*1080 = 25,920 parts in one day.

Hence there are 7*25920 = 181,440 parts in one week.

Since there are no common factors between 7 and 25920 we must go for
7*25920 = **181,440** months before the time of a given molad is repeated.

For example, the molad of Tishrei 1H, **BaHaRad**, will return
as the molad of Sivan 14,670H (Mon 23 Jun 10,910g) and again 181,440 months
later as the molad of Tevet 29,340H (Mon 7 Apr 25,580g).

**BaHaRad** will not be repeated as a molad of Tishrei until
**117,358H (Mon 4 Jan 113,599g) **.

By one of these delightful coincidences, in the full Hebrew calendar cycle
of 689472 years, **BaHaRad** is also the very first molad of Tishrei that
will be repeated as a molad of Tishrei.

In the full Hebrew calendar cycle of 689472 years, how often do the

moladot of Tishreirepeat themselves?

The time of any molad is usually given as day, hour, minute and part.

There are 24*60*1080 = 25,920 parts in one day.

Hence there are 7*25,920 = **181,440 parts** in one week.

Since there are no common factors between 7 and 25,920 we must go for
7*25920 = **181,440** months before the time of a given molad is repeated.

Since there are only 181,440 possible values for the moladot, the average
number of times that any molad of Tishrei can be repeated is
**689,472 / 181,440 = 3.8** repetitions.

In the full Hebrew calendar cycle of 689472 years, any molad of Tishrei is
repeated either **exactly 3 times or exactly 4 times**.

For example, the molad of Tishrei 1H, **BaHaRad**,
(Monday, September 7, -3760g) is repeated 4 times in the full Hebrew
calendar cycle. That molad will next occur for the following Hebrew years

117,358H | 04 Jan 113,599g |

308,063H | 16 Apr 304,306g |

498,768H | 26 Jul 495,013g |

689,473H | 04 Nov 685,720g |

What fraction of the

moladot of Tishreiare repeated exactly 3 times in the full Hebrew calendar cycle of 689,472 years?

The moladot of Tishrei can be repeated either exactly 3 times or exactly 4 times in the full Hebrew calendar cycle of 689,472 years.

There are 181,440 possible values for the moladot of Tishrei and all are represented at least 3 times in the full Hebrew calendar cycle.

Therefore, the fraction of the moladot of Tishrei which are repeated exactly 3 times in the full Hebrew calendar cycle of 689,472 years isLet T = the number of moladot that are repeated exactly 3 times Let F = the number of moladot that are repeated exactly 4 times Then T + F = 181,440 (the total number of possible moladot) 3*T + 4*F = 689,472 (the number of moladot of Tishrei in the full cycle) Hence, T = 36,288 which = 1/19 of 689,472 And 3*T = 98,064 which = 3/19 of 689,472

Correspondent **Moshe Alfred Silberman** sent the following very
interesting observations**.**

I enjoy your page dealing with the calendar very much. I have a question regarding your statement about the Molad always occurring prior to the second of the month. I will present the following assumptions and calculations and please tell me where I am wrong. 1. Rosh Hashana is Thursday/Friday. 2. Molad is on Thursday @ 17:59 Jewish time (which is 11:59AM according to our clocks). This would be the latest that it can occur befor Dechiya # 2 kicks in. 3. Year has 354 days and runs regular. 1. Tishrei Rosh Chodesh = Thu Molad = Thu @ 18 + 000 Chalakim (- 1 minute) 2. MarCheshvan Rosh Chodesh = Fri / Sat Molad = Sat @ 06 + 793 Chalakim (- 1 minute) 3. Kislev Rosh Chodesh = Sun Molad = Sun @ 19 + 506 Chalakim (- 1 minute) 4. Teves Rosh Chodesh = Mon / Tue Molad = Tue @ 08 + 219 Chalakim (- 1 minute) 5. Shevat Rosh Chodesh = Wed Molad = Wed @ 20 + 1012 Chalakim (- 1 minute) 6. Adar Rosh Chodesh = Thu / Fri Molad = Fri @ 09 +725 Chalakim (- 1 minute) 7. Nissan Rosh Chodesh = Sat Molad = Sat @ 22 + 438 Chalakim (- 1 minute) 8. Iyar Rosh Chodesh = Sun / Mon Molad = Mon @ 11 + 151 Chalakim (- 1 minute) 9. Sivan Rosh Chodesh = Tue Molad = Tue @ 23 + 944 Chalakim (- 1 minute) 10. Tammuz Rosh Chodesh = Wed / Thu Molad = Thu @ 12 + 657 Chalakim (- 1 minute)11. Av Rosh Chodesh = Fri Molad = Fri @ 25 + 370 Chalakim (- 1 minute)12. Elul Rosh Chodesh = Sat / Sun Molad = Sun @ 14 + 83 Chalakim (- 1 minute)

Correspondent ** Moshe Alfred Silberman** has put forward a very good
paradox which appears to refute the fact that ** Dehiyyah Molad
Zaqen** solves the

How does Silberman's Paradox fail to disprove the fact that

Dehiyyah Molad Zaqensolves the Overpost Problem?

Correspondent **Moshe Alfred Silberman** sent the following very
interesting observations**.**

1. Rosh Hashana is Thursday/Friday. 2. Molad is on Thursday @ 17:59 Jewish time (which is 11:59AM according to our clocks). This would be the latest that it can occur befor Dechiya # 2 kicks in. 3. Year has 354 days and runs regular. 1. Tishrei Rosh Chodesh = Thu Molad = Thu @ 18 + 000 Chalakim (- 1 minute) 2. MarCheshvan Rosh Chodesh = Fri / Sat Molad = Sat @ 06 + 793 Chalakim (- 1 minute) 3. Kislev Rosh Chodesh = Sun Molad = Sun @ 19 + 506 Chalakim (- 1 minute) 4. Teves Rosh Chodesh = Mon / Tue Molad = Tue @ 08 + 219 Chalakim (- 1 minute) 5. Shevat Rosh Chodesh = Wed Molad = Wed @ 20 + 1012 Chalakim (- 1 minute) 6. Adar Rosh Chodesh = Thu / Fri Molad = Fri @ 09 +725 Chalakim (- 1 minute) 7. Nissan Rosh Chodesh = Sat Molad = Sat @ 22 + 438 Chalakim (- 1 minute) 8. Iyar Rosh Chodesh = Sun / Mon Molad = Mon @ 11 + 151 Chalakim (- 1 minute) 9. Sivan Rosh Chodesh = Tue Molad = Tue @ 23 + 944 Chalakim (- 1 minute) 10. Tammuz Rosh Chodesh = Wed / Thu Molad = Thu @ 12 + 657 Chalakim (- 1 minute)11. Av Rosh Chodesh = Fri Molad = Fri @ 25 + 370 Chalakim (- 1 minute)12. Elul Rosh Chodesh = Sat / Sun Molad = Sun @ 14 + 83 Chalakim (- 1 minute)

Correspondent ** Moshe Alfred Silberman** has put forward a very good
paradox which appears to refute the fact that ** Dehiyyah Molad
Zakein** solves the

However, the weakness of the demonstration lies in the fact that
** the molad of Tishrei of any 354 day year cannot be more than 9h 203p
on either Tuesday or Thursday**.

Let R = start day of Rosh Hashannah for Hebrew year H Let R' = start day of Rosh Hashannah for Hebrew year H + 1 Then R' - R = 354 daysLet t = time of molad of Tishrei for year H Let t' = time of molad of Tishrei for year H + 1

Then R + t + 354d 8h 876p = R' + t' t = R' - R - (354d 8h 876p) + t' t = t' - (8h 876p)

Since the maximum value for t' is 17h 1079p on day R' the maximum value for t = (17h 1079p) - (8h 876p) = 9h 203p

Some correspondents did not see the coincidence, and suggested this result to be a perfectly logical consequence of the fact that BaHaRaD is the first molad of Tishrei in the full Hebrew calendar cycle.

If that is the case, then the 2nd molad of Tishrei in the full Hebrew calendar cycle should be the 2nd molad of Tishrei to be repeated.

First Begun 21 Jun 1998 First Paged 5 Nov 2004 Next Revised 5 Nov 2004