When is Shabbos Over?
Rabbi Yaakov Hoffman
Washington Heights Congregation

Determining when Shabbos concludes has always been a weekly necessity for observant Jews.
Thus, one might assume that everyone ends Shabbos at more or less the same time. In actuality, there isa great deal of variation. Some people commence weekday activities on Saturday night 40 minutes aftersunset, while others wait longer—some as long as two hours after sunset. How could it be that there issuch a range?
Compounding the question is the fact that the Gemara itself seems to rule that Shabbos is overquite early. Shabbos ends at halachic nightfall, which is heralded by the appearance of three mediumsized stars (tzeis ha-kochavim). The Gemara states that nightfall occurs when the amount of time has
passed after sunset that one could walk three-quarters of a mil (Shabbos 34b). This is at most 18
minutes.1
Granted, some interpret the Gemara’s conclusion to mean that tzeis ha-kochavim actuallyoccurs a bit later than three-quarters of a mil after sunset.2 But people nowadays wait much longer than18 minutes after sunset to end Shabbos. Why?
The answer is threefold: First of all, the time it takes darkness to fall is variable depending on theseason and location. The amount of time the Gemara gives between sunset and nightfall is only anapproximation.
Second, it is not entirely clear that what the Gemara calls “sunset” (shki‘as ha-chama or
mishetishka‘ ha-chama) is the same as what we call sunset today—i.e., when the top of the body of thesun dips below the horizon. Talmudic sunset may actually be a bit later, when the sun’s bright rays
disappear.3 For these two reasons, we must follow the actual appearance of stars to determine tzeis hakochavim, not a fixed amount of time after what we call sunset.

1This figure assumes that a mil is 24 minutes. According to the opinion that a mil is 18 minutes, three-quarters of amil would be even less: 13.5 minutes.
2
In this interpretation, it is only R. Yehuda who holds that nightfall is three-quarters of a mil after sunset;
according to R. Yose, tzeis ha-kochavim occurs slightly later. However, many authorities maintain that nightfall is at
an identical time according to both R. Yehuda and R. Yose. See Rabbi Chaim P. Benish, Ha-Zemanim Ba-Halacha,chapter 40, paragraphs 8-10.
3
See Rabbi Meir Posen, Or Meir, chapter 3; Rabbi Gidon Rothstein in BDD 14 (2004); Rabbi Yosef Qafih’scommentary to Rambam Hilchos Shabbos chapter 5 note 14; Rabbi M.M. Karp’s monograph in the back of Hilchos
Shabbos Be-Shabbos volume 4.

A third reason that our practice seems more stringent than the Gemara is that we are no longer
proficient at identifying which stars are considered “medium-sized.” Shulchan Aruch, following earlier
authorities, rules that we must actually wait until three small stars are visible, at least where a Biblicallaw is concerned (O.H. 235:1). On Motzaei Shabbos, we must be even more stringent and wait until
three small stars are visible close together in the sky. This is due to the requirement of tosefes Shabbos(adding extra time to Shabbos; see O.H. 293:1).
Most of us nowadays are not adept at identifying the required stars at all—either because we
do not know how, or because light pollution from electric illumination obscures them. Therefore, wegenerally determine the time of tzeis ha-kochavim by consulting a calendar.
The time given in the calendar is based on an astronomical calculation: One ascertains how far
the sun must descend below the horizon to produce a level of darkness sufficient to view the requisitestars. By extrapolating when a similar solar position occurs for the target date and location, one cancompute the appropriate time for tzeis ha-kochavim.4
Most contemporary calendars and zmanim apps adopt the calculation of Rabbi Yechiel M.
Tukacinsky (1871-1955), which is that “three small stars close together” appear when the sun has
descended 8.5 degrees below the horizon.5 In New York, the sun attains a depression angle of 8.5
degrees approximately 40 minutes after sunset at the equinox, and as late as 51 minutes in the summer.
Unfortunately, many twentieth-century New York calendars gave an oversimplified time for theclose of Shabbos. Since most people were cognizant of the time for Friday candle lighting (18 minutesbefore sunset), for convenience’s sake these calendars calculated Motzaei Shabbos as one hour
thereafter (42 minutes after sunset). Now that the accurate calculation of 8.5 degrees is readily
accessible, there is no more excuse for relying on fuzzy math. If one insists on using a fixed number ofminutes after sunset rather than astronomical calculation, 50 minutes would be more appropriate.64See a concise explanation of this at https://www.myzmanim.com/read/sources.aspx .
See Ha-Zemanim Ba-Halacha chapters 51-52 for other calculations. Although some of these are actually earlier
than 8.5 degrees, it behooves us err on the side of stringency in this very serious matter. In fact, waiting a few
minutes after 8.5 degrees would be appropriate when possible. I heard from Rabbi Emanuel Gettinger that in New
York, it is proper to refrain from performing forbidden labor until one hour after sunset.
6Cf. Iggros Moshe O.H. 4:62. Hazon Ish held a similar opinion.
5

So why do some people end Shabbos considerably later than when the sun has descended 8.5
degrees? Those who are more stringent claim to base their practice on the opinion of Rabbeinu Tam,
who reinterprets the Gemara’s discussion of halachic nightfall. While others consider them synonymous,
Rabbeinu Tam distinguishes between the two Talmudic terms for sunset: shki‘as ha-chama refers to thebeginning of the sun-setting process (Psachim 94a, see Tosafos ad loc.); mishetishka‘ ha-chama, thesecond stage of sunset, occurs 3.25 mil later (Shabbos 34b and Tosafos ad loc.). Shki‘as ha-chama, thefirst sunset, is generally identified with what we call sunset—the top of the sun disappearing below thehorizon.7 The second sunset (mishetishka‘ ha-chama) is thus at least 58.5 minutes after what we callsunset.8
In Rabbeinu Tam’s view, nightfall is three-quarters of a mil after the second sunset. Depending
on how precisely one interprets Rabbeinu Tam’s opinion, tzeis ha-kochavim is either 72,9 90,10 or 120
minutes after what we call sunset.11 If one further applies the principle of calculation based on solar
depression angle,12 the amount of time between sunset and nightfall can increase even more.13
The most common variant of “Rabbeinu Tam’s nightfall” as practiced nowadays is 72 fixedminutes after sunset.14 Individuals of diverse backgrounds have adopted this stringency, and it isvirtually standard in many Hasidic and yeshivish communities.15
Actually, referring to the late version of Motzaei Shabbos as “Rabbeinu Tam” is a misnomer, as it
implies that Rabbeinu Tam is a lone opinion on the matter. In fact, most early commentators andShulchan Aruch concur with Rabbeinu Tam (O.H. 261:2). The question now becomes reversed: Why iskeeping Shabbos until “Rabbeinu Tam’s time” not a universal Jewish practice?

7See, e.g., Mishnah Berurah 261:20.
If a mil is 18 minutes, 3.25 mil equals 58.5 minutes. If a mil is longer, the time increases accordingly.
9Since there are 3.25 mil from the first sunset to the second, and 0.75 mil from the second sunset to nightfall, thetotal amount of time from the “beginning of sunset” to nightfall is 4 mil. 4 mil of 18 minutes equals 72 minutes.
104 mil according to the opinion that the mil is 22.5 minutes.
11
120 minutes assumes that there are actually 5 mil between beginning of sunset and nightfall. A corollary to thisopinion is that the mil is 24 minutes.
12This would assume that nightfall is 72 minutes after sunset in Jerusalem at the equinox, when the sun is 16.1
degrees below the horizon. In many current and former Jewish communities, such as London and Vilna, the sundoes not descend to this level at all in the summer (cf. Bei’ur Ha-Gra to O.H. 261:2). Furthermore, if nightfall
according to Rabbeinu Tam is actually 90 or 120 minutes after sunset, this time is past absolute darkness(astronomical twilight) in Jerusalem at the equinox. All stars have already appeared by that time!
13
There is also the famous “Brisker” approach which calculates these times by way of sha‘os zmaniyos(proportional hours). According to the Brisker practice, Rabbeinu Tam’s tzeis ha-kochavim is earlier in the winterthan at the equinox. This is the opposite of astronomical reality, which is that it takes longer to become dark in thewinter than at the equinox.
14
While in New York waiting 72 minutes after sunset to end Shabbos always results in stringency, one must beaware that the same does not pertain to all locales. In northerly places such as England, 8.5 degrees occurs later
than 72 minutes after sunset in the summer.
15
See Yabia Omer O.H. 2:21 regarding the Sefardic community.
8

Truth be told, it is far from clear that Rabbeinu Tam and Shulchan Aruch really require such alate ending to Shabbos. Figuring out when Shabbos ends according to the aforementioned approachnecessarily involves consulting an accurate clock or a precise astronomical calculation, both of whichwere generally unavailable for the vast majority of Jewish history. Jews determined all halachic times bycelestial observation or by reading a sundial. Except in extremely northern locales, the sky is dark andfilled with stars well before the time people claim is tzeis ha-kochavim according to Rabbeinu Tam.16Indeed, many contemporary works argue that Rabbeinu Tam never intended to establish a noveltime for tzeis ha-kochavim.17 Rather, he only intended to reanalyze the process of halachic sunset. In
other words, Rabbeinu Tam’s insight is that the “beginning of sunset” occurs 72 minutes before threestars appear, not that tzeis ha-kochavim is 72 minutes after what we call sunset.18
The actual practice of the Jewish people from time immemorial supports the contention thatRabbeinu Tam never disagreed about the time of tzeis ha-kochavim. Rabbi Chaim P. Benish, in his book
Ha-Zemanim Ba-Halacha, musters clear evidence that until quite recently, all communities ended
Shabbos when they actually observed three stars, including those that claimed to follow the opinion ofRabbeinu Tam (see chapters 44-46).
The fact that it is so common nowadays to observe Shabbos until 72 minutes after sunset
despite the incongruence with astronomical reality and historical practice can probably be attributed tothe breakdown of the living religious tradition during the upheaval of the World Wars.19
In conclusion, the commonly accepted time for ending Shabbos, Yom Tov, and Yom Kippur iswhen the sun has descended 8.5 degrees below the horizon. In New York, this is at most 51 minutes
after sunset. Many individuals and communities keep Shabbos even longer, which is certainly acommendable custom.20 However, the prevalent practice is eminently halachically sound and reflects
the historical practice of the Jewish people.

16

It is obviously extremely difficult to argue that all the stars that appear before 72 minutes after sunset are“large” stars, and the “medium-sized” stars that indicate tzeis ha-kochavim appear only thereafter.
17
The most expansive presentation of this view is Yom Va-Layla shel Torah by Rabbi Y.G. Weiss. The most concise
is Rabbi M.M. Karp’s monograph, printed in the back of Hilchos Shabbos Be-Shabbos volume 4. See also theliterature cited in Ha-Zemanim Ba-Halacha chapter 42 paragraph 20.
18This would explain why the only place Shulhan Aruch cites Rabbeinu Tam’s view is regarding the earliest time toaccept Shabbos (O.H. 261:2, following Ramban in Torat Ha-Adam). Everywhere that Shulhan Aruch mentions tzeis
ha-kochavim, he simply states that it is when three stars appear (see O.H. 235:1 and 293:1, cf. Y.D. 262:5). Thisimplies that Rabbeinu Tam’s insight is irrelevant for determining the time of nightfall. This is also the implication ofthe fact that all early sources that cite Rabbeinu Tam’s opinion give no indication that it had any impact on thetime for ending Shabbos.
19Cf. Haim Soloveitchik, “Rupture and Reconstruction: The Transformation of Contemporary Orthodoxy” inTradition Vol. 28, No. 4 (Summer 1994), available online here.
20However, it is completely unacceptable even to consider the possibility that tzeis ha-kochavim is 72 minutes (ormore) after sunset when this would result in a leniency (e.g. for praying mincha, hefsek tahara, etc.). See Rabbi
Gavriel Zinner, Nit‘ei Gavriel Hilchos Shabbos, vol. 1 p. 929ff.