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Obligatory Summary The Jewish day starts at night, but V'sein Tal Umatar is based on solar calendar, so it can sometimes be a day later. Plus the date was established in Julian Calendar, so there's also the Julian->Gregorian shift to keep us busy... Real Answer The Gemara (Taanis 10a) says that in Bavel we start saying V'sein Tal Umatar on the 60th day ...


32

There is no way to know for certain. However, there are a few indications that what we have the "correct" day. Firstly, there is the halacha that if you do not know what day it is, you keep Shabbat on the 7th day from the last time you kept shabbat. So even if the calendar did a shift, presumably the Jewish people would have shifted the name of the ...


25

We do not determine the date of the Sabbath by looking at the calendar and seeing which day is Saturday (or Friday night). Rather (much like my answer to the Samoa" question) the Sabbath is seven days from the previous Sabbath. We have a living mesorah, tradition, on which day is the Sabbath, which happens to coincide with what it commonly known as Friday ...


21

There are definitely some specially celebratory ones other than age 13, such as when one surpasses the deadline for kares, as Rav Yosef did when he turned 60 and threw himself a party (Mo'ed Katan 28). The Kaf Hachayim, cited in this article by Rav Ari Enkin, also quotes sources for age 70 being an appropriate birthday to recite birkas shehechiyanu (...


21

Yes. The website uses UTC time. Since I live on the west coast in the US, each "website day" starts at 5 PM. Thus, I simply visit the site after 5 PM on Friday, which during the summer months is not yet Shabbos, and then visit again before 5 PM on Sunday. As far as the website is concerned, I just visited on two consecutive days. The only remaining problem ...


21

The last shemittah year was Jewish year 5768 (13 Sept 2007 - 29 Sept 2008) The next few are: 5775 (25 Sept 2014 - 13 Sept 2015) 5782 (7 Sept 2021 - 25 Sept 2022) 5789 (21 Sept 2028 - 9 Sept 2029) Note that some Rishonim (medieval rabbis) held that the shemittah is the year prior to the years mentioned above (See Tur CM 67) but longstanding normative ...


20

In Sanhedrin 65b (line 24 and further) Tornosrufus asked same question to R. Akiva. R. Akiva answered that there are three proofs that the day Jew think is Shabbos is a real Shabbos. River Sebation is very fast on other days and on Shabbos it streams slowly. Baal Ov couldn't be applied on Shabbos. Smoke comes out of the grave of Tornosrufus's father each ...


20

The epoch for the Jewish calendar is the creation of the world, not the Revelation at Sinai which traditionally occured about 2500 years later and marks the beginning of distinctly Jewish national religious obligations.


18

In Tanach there are only four: Aviv = first month = Nissan (Ex. 13:4, et al) Ziv = second month = Iyar (I Kings 6:1) Eisanim = seventh month = Tishrei (ibid. 8:2) Bul = eighth month = (Mar)cheshvan (ibid. 6:38) In a letter from the era of the first Beis Hamikdash found in Arad, there is mention (according to some reconstructions) of ירח צח, "the month ...


18

There is some discussion in the Jerusalem Talmud (M'gilla 7a-b) regarding which of the two Adars is considered the leap month (incidentally, halachic ramifications are discussed ad loc.). Medieval commentators interpret the Talmud as concluding that Adar I is the extra month (see Rashi to Rosh HaShana 19b, s.v. kamma ibbur hashana; see also Tosafos ibid., s....


18

Actually, Miketz does not always fall out on Chanukah. It appears that whoever told me that was mistaken. :) I ran some code (using my JavaScript Hebcal API) and discovered that in the 100 years from 5700-5800, Miketz is not on Chanukah 10 times. In 5703, 5706, 5710, 5730, 5733, 5737, 5757, 5761, 5781, and 5784, Miketz fell out on the 4th of Tevet, just ...


16

Let's take a step back: the Hebrew calendar uses lunar months of either 29 or 30 days (for 354 days altogether). Now the Bible says that Passover should be in the spring, and if you keep having years of 354 days you'll keep sliding backwards until Passover won't be in the spring anymore, so every so often they'd add a leap month. Sure, other peoples may have ...


15

R' Moshe Feinstein zt"l explains (Igros Moshe, vol. 8, Yoreh De'ah 57:11) that the statement in the kinah is referring to tragedies affecting all of the Jewish people. The Crusaders wanted a wholly Christian world, with no Jews ר"ל (and indeed, they attacked and killed the Jews in Jerusalem as well as in Europe); Hitler's ימ"ש aim was similar. Such ...


15

Seder Olam Rabbah, by R. Yosei ben Chalafta (2nd century), gives a unified chronology from Creation until his own times (although the last part of it, covering the Second Temple era and its aftermath, is given pretty short shrift). The Gemara (Avodah Zarah 9b) quotes a baraisa (also from, at the latest, the 2nd or early 3rd century) that makes a prediction ...


15

The discrepancy has been raised repeatedly over the centuries, by scholars Jew and non-Jew, Orthodox or not, alike. Rabbi Shimon Schwab penned an essay on it whereby he very much raised the possibility that the non-Seder-Olam chronology may be correct, though later referring to it as a "thought experiment." In his taped lectures on the history of the ...


14

He is saying that the year 3724 coincides with the end of a 532-year calendrical cycle. This cycle is when the 19-year machzor katan and the 28-year machzor gadol return to their initial positions (19 x 28 = 532). The year 3724 comes after exactly 7 of those cycles (532 x 7 = 3724). He does not explain why this has any significance. UPDATE: Mevaqesh's ...


14

Rashi in the linked Gemara says that the reason we are "marbim b'simcha" is because they are "ymei nisim k'mo Purim v'Pesach" based on which some conclude that Adar Rishon is not included, as no miracles happened in that time period. The Levush (685:1) says that we do not increase simcha in Adar 1. The Sfas Emes says we do. Some want to conclude based on ...


14

This is discussed in the Talmud (Shabbat 114) and the Rambam rules (Shabbat 5:21) that no Havdallah is recited after Shabbat when Yom Kippur falls on Sunday.


13

After some much Hebrew googling, it seems as though the rationale is the other way around. Adar was doubled because it was the last month of the calendar (which started at Nisan with Passover) back then. The decision was to celebrate Purim (and all the other events) in the second Adar as to keep both redemption celebrations close (Purim and Passover). ...


13

You are correct that the .NET implementation is apparently not consistent with Halacha (i.e. Jewish law) (Orach Chaim 55:10 and Mishne Berurah ibid) and your first 2 rules are correct and consistent with Halacha. Jewish law (ibid, MB 45) calculations are correctly implemented in HebCal contrary to your third rule. Specifically, if a boy is born on 30 ...


13

Your question and DoubleAA's comment on my original answer have inspired me to do some research and learn some really fascinating information about the Hebrew calendar. First, some background information: Our current 19-year intercalary cycle was instituted by Hillel II in the fourth century CE. The calendar is a lunisolar calendar which typically has 12 ...


13

While the Jewish holidays are controlled by the Sanhedrin (though, notably, they are not controlled by non-Jewish governments, and even the Sanhedrin's control is bound by divinely received rules), Sabbath is different in that it always repeats every seventh day, regardless of any calendar. This is one reason given why, in the central prayer of Sabbath/...


12

Nitei Gavriel cites sources that say that in that case the people in Eretz Yisrael indeed start saying Pirkei Avos on Shabbos the 22nd of Nissan and continue from there, so that they recite the sixth chapter on the sixth Shabbos of the Omer. For the seventh Shabbos, then, they study the first chapter of Maseches Derech Eretz Zuta. (He actually says ויש ...


12

HebCal is a full Hebrew calendar that provides lists of all the Jewish holidays, for any year. In the interest of full disclosure, i have done volunteer programming for them, but am not officially affiliated. Here is a list of all the Jewish holidays for the year 5775 (this year). Note that not every item on that list is a full holiday where work is ...


11

In the Hagada Shel Pesach Gevuras Akiva he explains that the Rama is the one who holds that you should say Baomer, and Lag Baomer is the Yarzeit of the Rama. therefore in honor of the Rama everyone calls the day Lag Baomer.


11

Perhaps because each of the dates commemorate multiple things. Five Tragedies happened on the 17th of Tammuz: Moshe broke the Tablets The Tamid offering was interrupted A Sefer Torah was burned An idol was placed in the Beit Hamikdash The walls of Jerusalem were breached during the second temple The 9th of Av has always been a day of tragedy, and many ...


11

Considering Monica's point about year distributions, here's a refinement of Gershon's data (using the frequency table on Remy Landau's Hebrew Calendar page, here): Tzom Gedaliah falls on Monday or Thursday in the year types גכה, זחא, זשג, גכז, זחג, זשה. This is 40.08% of all years. Asarah B'Teves can't occur on Monday, but it can be on Thursday, only in the ...


11

According to Rabbi Israel Joseph haCohen Rappaport, the earliest time that you can start saying Shnayim Mikra B'Dieved is from Shabbos Mincha for the next week and L'Chatchila from Sunday.


11

I wondered about this fact myself for a while, and so I looked up the sources. It turns out that this idea is based on only two sources. The Talmud has an aggadatot which says: Talmud, Tractate Sanhedrin [97a]: “Rav Kattina said: ‘The world will exist for 6000 years and one (thousand) of destruction’ ... We have a teaching which is in agreement ...


11

The Ritva writes (Rosh Hashana 11a): ויומי ניסן לאו דוקא אלא כל מקום ומקום לפי מה שהוא דמלבלבי.‏ "The days of Nissan" is not precise, but rather every place according to when the trees bud. Based on this, Rabbis Yitzchok Yaakov Weiss (Minchat Yitzchak 10:16) and Tzvi Pesach Frank (Har Tzvi OC 118) ruled that in the Southern Hemisphere the blessing ...


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