This was written to be a quick, simple read, the sources are all footnoted.
The gemara in Shabbat 35a, determined1 that shabbat ends as a stringency2 (timewise) at ¾ mil3,4 after sunset or (visually) by looking at the sky5 6 and seeing three stars. These two methods7 result in the same time-frame as confirmed by everyone8 from Vilna Gaon9 to modern day astronomers10.
People who wait 4 mil based on their understanding of R'Tam erroneously conclude13 that shabbat ends 4 mil after sunset per the gemara in Pesachim14, 15 (72 minutes) by saying the gemara in shabbat means ¾ mil after a “later” sunset. According to this misunderstanding, it is still considered day until 3 ¼ mil after the actual sunset (58.5 minutes) and one may do melacha on erev shabbat and daven mincha until then16 as it is still day.
This error is based on the typical understanding of R' Tam as 4 mil after sunset, and that where R’ Tam lived11 it was impossible to see 3 stars at ¾ mil after sunset12 so he erroneously (in their view) concluded13 that shabbat ends per the gemara in Pesachim14,
This misunderstanding is factually wrong and it’s chillul shabbat to perform melacha deoryta17 on Friday after sunset or to daven mincha after sunset18. Subsequently, there is no legitimate reason whatsoever to wait more than ¾ mil after sunset to end shabbat. Those who claim to follow R’ Tam zman are deluding themselves as they and their ancestors in Europe definitely did not not keep his ruling of 4 mil19.
One may see lots of other times for ending shabbat on a calendar, however, they are completely wrong, and in the words of R’ Ovadia Yosef “The times published in the calendars have no basis whatsoever in halacha. They are not ¾ mil and they are not R’ Tam.”20 Some poskim have added all kinds of ideas, like waiting for 3 medium sized stars21, 3 small stars, 3 stars all together etc. Some have claimed even longer times by saying that we are not experts on stars today etc. This is wrong because the gemara gave us ways to determine: Either 3 stars, or ¾ mil. We don’t need to be experts or even see the 3 stars, we can trust chazal that at ¾ mil shabbat has ended.
Keeping shabbat for longer than ¾ mil is a mitzvah called tosefet shabbat. In fact one must add on to shabbat before and after any amount of time no minimum.
The key and most important takeaway is not necessary when one should physically end shabbat, but rather how long is bein hashmashot and when shabbat actually ends. The reason this is so important is because:
- If one thinks shabbat is over at 30, 42, 50, 72, 90 or any other minutes after sunset, they have lost the valuable mitzvah of tosefet shabbat as mitzvot require intent. Rather, one can realize shabbat has ended at the location adjusted 13.5 minutes22 after sunset and perform the mitzvah of tosefet shabbat for the duration of time until they physically end shabbat.
- If one must do something immediately after shabbat to know the actual time that shabbat has ended.
- Using a bein hashmashot longer than ¾ mil can lead to chillul shabbat because the halacha allows one to do melacha derabanan during bein hashmashot22. Using a “longer” bein hashmashot than ¾ mil, is chillul shabbat.
1. אָמַר רַבָּה בַּר בַּר חָנָה אָמַר רַבִּי יוֹחָנָן: הֲלָכָה כְּרַבִּי יְהוּדָה לְעִנְיַן שַׁבָּת
2. This timeframe of ¾ mil is is a stringency as the gemara debates whether it is ⅔ of a mil of ¾ mil and concludes to go l’chumrah, הֲלָכָה כְּרַבִּי יְהוּדָה לְעִנְיַן שַׁבָּת — לְחוּמְרָא
3. The time it takes to walk ¾ of a mil. A mil is 18 minutes. 3/4 of a mil is 13.5 minutes.
While there are those who claim (as a stringency) a mil to be 22 or 24 minutes, in reality nobody in practice believes that a mil is 24 minutes, because when it comes to baking matzah everyone assumes a mil is 18 minutes.
Incidentally, and not related, the 18 minute time assumed that dough becomes chametz is wrong, it’s actually 4 mil. This is just another extreme concept that has gone mainstream. Finally, even if it were 18 minutes, it is 18 minutes from when the dough is left untouched, not the 18 minute start to stop that is practiced - which has no basis whatsoever.
4. This 3/4 mil (13.5 minutes) was based in Bavel or Jerusalem on equinox date, where discussions in the Talmud are based on and written. This length of time will be greater in other locations.
The ability to see stars is based on how dark the sky is. The level of darkness in the sky is based on how far the sun has sunk below the horizon. This is called depression degrees.
Given that the Talmud Bavli was written in Bavel (nowadays Baghdad) every posek agrees that the level of darkness discussed in the talmud of ¾ mil is measured based on Baghdad which is at -3.5°. Incidentally both Jerusalem and Baghdad reach the -3.5° depression angle at the same time of 13.5 minutes.
This same -3.5° is about 19 minutes in Vilna or Troyes where R’ Tam lived. Today, all poskim agree that the zemanin are latitude based, ie. depression degrees. This is also used by all astronomers.
5. אָמַר רַב יְהוּדָה אָמַר שְׁמוּאֵל: כּוֹכָב אֶחָד — יוֹם, שְׁנַיִם — בֵּין הַשְּׁמָשׁוֹת, שְׁלֹשָׁה — לַיְלָה. תַּנְיָא נָמֵי הָכִי: כּוֹכָב אֶחָד יוֹם, שְׁנַיִם בֵּין הַשְּׁמָשׁוֹת, שְׁלֹשָׁה לַיְלָה.
6. R’ Yossi, which the gemara determined has a later time, which is clearly not used for ending shabbat but rather for tumah, “ אָמַר רַבָּה בַּר בַּר חָנָה אָמַר רַבִּי יוֹחָנָן: הֲלָכָה כְּרַבִּי יְהוּדָה לְעִנְיַן שַׁבָּת, וַהֲלָכָה כְּרַבִּי יוֹסֵי לְעִנְיַן תְּרוּמָה” adds that his timeframe is 3 medium stars, which is later. אָמַר רַבִּי יוֹסֵי, לֹא כּוֹכָבִים גְּדוֹלִים הַנִּרְאִין בַּיּוֹם, וְלֹא כּוֹכָבִים קְטַנִּים שֶׁאֵין נִרְאִין אֶלָּא בַּלַּיְלָה — אֶלָּא בֵּינוֹנִים. To be clear this has no relevance to shabbat ending according to the gemara.
7. This is when the sun is -3.5° below the horizon is the same as the time it takes to walk ¾ mil, 13.5 minutes.
8. See שולחן ערוך אורח חיים רס״א:ב “ושיעור זמן בין השמשות הוא ג' רבעי מיל שהם מהלך אלף ות"ק אמות קודם הלילה
9. ביאור הגר"א על שולחן ערוך אורח חיים רס״א:ב׳
10. I corresponded with 3 experts in astronomy and all confirmed that 3 stars are visible at -3.5°. These are Sirius (a star), Venus (a planet), Jupiter (a planet) and Mars (a planet). They said "These planets can be mistaken for stars but they don't twinkle like stars do."
11. Troyes, France
12. In Troyes the same -3.5° which is based on the ¾ mil in jerusalem/bavel is about 19 minutes (at equinox), which is longer than a full mil.
13. Almost every single scholar today recognizes that R’ Tam made a mistake in developing his theory based on his location.
14. Pesachim 94a
15. The gemara in Pesachim is not a contradiction to Shabbat, as everyone (except R Tam in error) agrees that Pesachim refers to when all the stars are out, nothing to do with shabbat ending.
16. Chassidim (who erroneously followed what they believe is R’ Tam's understanding) did melacha on Friday until 58.5 minutes after sunset. R’ Kotler met with the Satmar Rebbe and expressed his concern that non chassidim observing chasidim doing melacha after sunset would lead them to believe it was permissible for them as well. They reached a compromise whereby everyone would start Shabbat at sunset, and the yeshivish world would end shabbat with the chassidim at 72 minutes after sunset.
17. One may perform melacha derabana until ¾ mil after sunset, since the bein hashmashot period is considered to be unsure if day or night, and the rule by derabana is when in doubt to be lenient. This is per the gemara in Shabbat 34a and mentioned in Shulchan Aruch. Mishna Brurah modifies the allowance to only asking a non-jew or doing melacha in a place where no jews live.
18. Even those poskim today who like to follow what they believe is R’ Tam will never allow melacha deoryta on Friday after sunset.
19. 72 minutes after sunset is a total mistake and is not in accordance with what people believe is R Tam’s unique understanding of the gemara, because that 4 mil, (72 minutes) would be based in Baghdad, which is the darkness level of -16°. Using -16° in Troyes, where R’ Tam lived would be between 90 and 108 minutes.
Even worse, the people in Vilna who followed the ruling of R’ Tam waited 72 or 90 minutes based on 4 mil. However, that is completely wrong. Based on -16° in Vilna, R’ Tam’s concept would be at earliest 108 minutes and up to 220 minutes. There is no record or anyone waiting in Vilna for more than 90 minutes, so as a fact, nobody in Vina kept R’ Tam and were actually acting in error.
In New York -16° is between 79 and 107 minutes, the 72 minute number is a total fabrication.
20. Yalkut Yosef Siman 293:2 וזמני צאת השבת המתפרסמים בלוחות רבים, אין להם כל יסוד בהלכה, שאינם לא לפי שיטת הגאונים [שלדעת מרן הוא י״ג דקות וחצי בשעות זמניות. ולדעת האומרים שהמיל הו כ״ד דקות, זמן צאת הכוכבים הוא י״ח דקות אחר השקיעה בשעות זמניות]. ולא לפי שיטת רבינו תם, שסובר שזמן צאת הכוכבים הוא שבעים ושתים דקות אחר השקיע בשעות זמניות
22. One must wait until it is at least -3.5° at their location plus a few minutes of tosefet shabbat to end shabbat. To easily check times go to https://www.myzmanim.com/ enter the location and then at the bottom of the zmanim one will see “Not all zmanim and opinions have been displayed. If you can't find the zman you're looking for click All zmanim'' Click All Zmanim and a note will pop up stating “Please do not rely on any of these zmanim without consulting a qualified Rav.” click “continue” and now you will see lots of zmanim. The only halachically based option is what they label as לילה לגר"א - ג' רבעי מיל Gra's nightfall - 3/4 mil. Note the first one which is based on an 18 minute mil and that is the correct time shabbat has ended.
23. Shabbat 34a “ בֵּין הַשְּׁמָשׁוֹת סְפֵקָא הוּא, וּסְפֵקָא דְרַבָּנַן לְקוּלָּא”