zmanim times

Zmanim (terms and times)

A shaa regila (regular hour) is a standard 60 minute clock hour and a daka regila (regular minute) is a standard clock minute.

The Magen Avraham reckons the length of the day from alot hashachar (90 minutes) till tzeit hakochavim (90 minutes). The GR"A reckons the length of the day from hanetz hachama until shkiat hachama. The number of real minutes in the day divided by 12 gives the number of minutes (and fraction) of a shaa zmanit. The same principle is also applied to the length of a daka zmanit (proportional minute).

All calendars that I have come across use the shaa zmanit of the GR"A for all calculations. The exception is when the times for sof zman shma (final time for the shema) and sof zman tefillah (final time for shacharit) are given using the shita of the Magen Avraham Then the shaa zmanit of the Magen Avraham is used for these calculations. Using the shita of the Magen Avraham, these times come out earlier than those of the GR"A so that those wishing to be strict in their observance will follow the shita of the Magen Avraham.

The Magen Avraham's shita is derived from the pasuk in 4 Nechemia, defining when the workers are performing their tasks (from alot hashachar till tzeit hakochavim). Due to inconsistencies between this method and references in the gemarah, the GR"A disagrees with the shita of the Magen Avraham.

In his elucidation of the Shulchan Aruch (באור הגר"א או"ח סי' תנט ב) the GR"A brings a gemarah in the Yerushalmi stating that there are times of the year that the day is the same length as the night, the GR"A therefore concludes that the correct method of the determing the day is from hanetz hachama till shkiat hachama, since only by this method can the length of the day be the same as the length of the night (this ocurring at the equinoxes).

The GR"A also brings down a particularly nice midrash:


מדרש רבה, משפטים, פרשה לא, טו אומר: לא תהיה לו כנושה. הה"ד טוב איש חונן ומלוה יכלכל דריו במשפט. בא וראה כל בריותיו של הקב"ה לווין זה מזה. היום לוה מן הלילה והלילה מן היום.
 
הפירוש מהרזו אומר: היום לוה. שבקיץ היום גדול ולוה היום מן הלילה ובחורף הלילה גדול ולוה מן היום. ובניסן ותשרי שניהם שוים ושלמו זה לזה.

What it comes down to is this: The Magen Avraham includes the two periods of doubt (alot hashachar till hanetz hachama and shkia till tzeit hakochavim) in his calculation of the length of the day. The GR"A however only includes "definite day" in his calculations. According to the GR"A, the length of the day is determined from hanetz hachama (which marks the end of the period of doubt from alot hashachar and the beginning of the definite day) till shkiat hachama (which marks the end of the definite day and the beginning of the period of doubt till tzeit hakochavim).

Where matters of length of the day are concerned, just about all poskim agree with the shita of the GR"A. Concerning matters of mitzvot which are dependent on time (day or night), both the GR"A and the M"A are in agreement that the day begins with alot hashachar and ends with tzeit hakochavim. This opinion is pretty much accepted by all poskim, although there might be one or two poskim that hold slightly differing opinions on this matter.

For an excellent, extensive (and for me exhausting) halachic discussion of the various aspects of day, see the entry day (יום) in the Encyclopedia Talmudit.

A shaa zmanit l'chumra is the same as a shaa zmanit, except in the winter. During the winter when the length of a shaa zmanit is shorter than a shaa regila (regular hour), a shaa regila (60 regular minutes) is used. Therefore, a shaa zmanit l'chumra can be longer than a shaa regila, but is not shorter. The same principle is applied to a daka zmanit l'chumra (strict proportional minute).

A shaa (and daka) zmanit l'chumra is generally only used to determine the time of mincha gedolah. It is also used sometimes to determine the time of motzei shabbat. The reason for using a shaa zmanit l'chumra arises from an uncertainty as to which type of hour or minute (regular or zmanit) should be used to determine mincha gedolah. Therefore some poskim use the shaa zmanit l'chumra as a compromise between a shaa regilah and a shaa zmanit.

I'm not sure that this is an halachic term. The term equivalent minutes is used by Yehuda (Leo) Levi in his book. I quote from Leo Levi's book:


These intervals may not be taken literally. They refer to Eretz Yisrael at the equinox. At other times of the year, the duration will be longer, even in Eretz Yisrael: and, as we go to higher latitudes, they become longer even at the equinox. [...] we refer to such intervals in terms of "equivalent" minutes.

The Hebrew "dakot shkulot" (דקות שקולות) is my term. This seems to be the closest term I could find to properly represent the concept. The phrase "dakot shkulot k'neged" (דקות שקולות כנגד) is probably a better representation of the idea, but it's too long - and doesn't fit well on the screen.

This number is calculated based on astronomical phenomena. Let's use alot hashachar as an example: According to the Rambam, alot hashachar is 72 regular minutes before hanetz hachama in Eretz Yisrael at the equinox. This corresponds to the sun being 16.1 degrees below the horizon. In other seasons, with the sun's position being the same, the number of minutes before hanetz increases during the summer, and decreases during the winter. Similarly at other locations, the time is calculated according to the sun's position in the sky relative to the desired location. This results in an interval different than that (72 regular minutes) of Eretz Yisrael.

This is the instant of the appearance of solar light in the eastern horizon. Transition from halachic night to halachic day. A period of safek (uncertainty), a mixture of day and night. Two primary shitot exist:
• the RAMBAM (72 equivalent minutes)
• the other Rishonim (90 equivalent minutes) - custom followed in Eretz Yisrael

This is the earliest time to put on the tallit and tefillin. Due to our inability to determine the precise time that "one can recognize a casual acquaintance from four amot", two main approaches exist:
• astronomical realities
• using a fixed amount of time before hanetz

The earliest time for tallit and tefillin in most communities in the diaspora and in many places in Eretz Yisrael is usually governed by astronomical realities. There are two prevalent shitot:
• the sun 11.0 degrees below the horizon (the Kaluach default)
• the sun 10.2 degrees below the horizon

It is common in Eretz Yisrael to follow one of the fixed time shitot. These shitot appear on most of the daily halachic calendars printed in Israel. There are two main shitot:
• the minhag of the gaonim of Sfarad - 60 minutes before sunrise (hanetz), this one seems to be the most common
• Ashkenazim and other adot - 50 minutes before sunrise (hanetz)

This is the instant that the first ray of the sun appears above the horizon.

Hanetz is a gerund meaning "the twinkling". Sometimes the term "netz" is used. Although this is theoretically grammatically incorrect, it is in common usage. I asked several rabbanim about this and they all said the term "netz" is correct. However the Even-Shoshan dictionary has no such citation.

This is the same as hanetz hachama. Although... I've also seen this (mistakenly) referred to as the instant that the entire sun appears above the horizon. Unfortunately, this can lead to confusion.

As far as I know, the appearance of the entire sun above the horizon has no halachic significance.

Two shitot are available - that of the Magen Avraham and that of the GR"A. The Magen Avraham adds three shaot zmaniot (computed from alot hashachar to tzeit hakochavim) to alot hashachar. The GR"A adds three shaot zmaniot (computed from hanetz hachama to shkia) to hanetz hachama. The shita of the GR"A ends up a little later in the morning than that of the Magen Avraham.

Two shitot are available - that of the Magen Avraham and that of the GR"A. The Magen Avraham adds four shaot zmaniot (computed from alot hashachar to tzeit hakochavim) to alot hashachar. The GR"A adds four shaot zmaniot (computed from hanetz hachama to shkia) to hanetz hachama. The shita of the GR"A ends up a little later in the morning than that of the Magen Avraham.

This is halachic noon, the midpoint of the day between sunrise and sunset (according to the GR"A) or between alot hashachar and tzeit hakochavim (according to the Magen Avraham). Kaluach presents the time of chatzot hayom according to the GR"A.

The earlist time for tefillat mincha is theoretically right after chatzot (midday). In practice however, there is a 30 minute delay is to avoid a safek (uncertainty). In the days of chaza"l they couldn't be sure when chatzot was exactly, so a half an hour was added. This might have been a proportional hour, or it could have also been measured as a fixed half-hour. Since they couldn't measure a proportional hour so easily, they more than likely measured it in much the same way as they did other times (such as tzeit hakochavim) - How long does it take someone to walk a certain distance.

This is the earliest time that tefillat mincha is permitted. There are three different shitot for determining the time of mincha gedola:
• 30 dakot regilot after chatzot hayom
• 30 dakot zmaniot after chatzot hayom
• 30 dakot zmaniot l'chumra after chatzot hayom

Nine and a half shaot zmaniot from the beginning of the day (alot hashachar according to the Magen Avraham, and hanetz hachama according to the GR"A). Based on the time that the korban mincha was brought into the Beit Hamikdash. Known as "ketanah" since the remaining two and a half hour period until sunset is shorter than the five and a half hour period of mincha gedola. Kaluach presents the time for mincha ketana using the shaa zmanit of the GR"A.

Refers to the splitting in half of the two and a half hour period of mincha ketanah.

Depending on which rabbinic opinions are adhered to, starting with plag hamincha, the following might be permitted:
• accepting Shabbat early
• lighting Chanukah candles
• tefillat aravit but only when absolutely necessary
• tefillat neilah on Yom Kippur

Due to the law of tosefet Shabbat (adding to Shabbat), Shabbat and the holidays start a certain number of regular minutes before shkia (sunset). The most common tosefet Shabbat appears to be 18 minutes, with some communities having their own minhagim (customs). For example, many residents of Jerusalem accept Shabbat 40 minutes before shkia (Petach Tikvah follows this Jerusalem custom). In a community with no custom or if unsure, it is best to accept Shabbat 30 minutes before shkia.

A common practice in some communities (Tel Aviv, Bnei Brak, Karnei Shomron) is to accept Shabbat 21 minutes before shkia. This is derived from the opinion of the Yeraim (one of the Rishonim) that bein hashmashot begins 18 minutes before shkia. A few minutes is added for the tosefet Shabbat. Since the Yeraim was actually referring to astronomic (equivalent) minutes, the 21 real minutes shita is theoretically incorrect. However, since we don't hold by the Yeraim concerning bein hashmashot, this really isn't a problem.

It's quite possible, although I haven't seen it written anywhere, that the 30 minute shita as observed by Beer Sheva and Haifa is an attempt at reconciling the shita of the Yeraim with today's usage of real minutes. By starting Shabbat 30 minutes before shkia, the observance of the Yeraim's bein hashmashot is also taken into consideration.

The instant the last ray of sun disappears below the horizon.

Transition from halachic day to halachic night. A period of safek (uncertainty), it is a mixture of day and night.

This is the ending of the bein hashmashot period. According to Leo Levi's book (Jewish Chrononomy) alone, there are five different shitot. Other halachic works appear to consider additional shitot.
In his book, Leo Levi states that the shita of the GR"A and the "120 minute" shita appear to have no halachic following. Some poskim however use the tzeit of the GR"A when a leniency is desired (eg. ending a fast on a minor fast day). Kaluach implements the shitot as presented in Leo Levi's book (except for the 120 minute shita). All of these shitot are based on astronomical phenomena and therefore the time period is not fixed, but rather varies depending on location and the time of year.

The "24 minute" shita of the Baal Hatanya appears to be the most commonly accepted tzeit hakochavim. There are also many who follow the more stringent "72 minute" Rabbenu Tam - although this shita is usually only used for tzeit Shabbat. The "26 minute" shita of the Baal Hatanya also has some following.

Rabbi Avrohom Altein provided me with a brief description of the 26 minute variation of the Baal Hatanya's tzeit hakochavim:
The Baal Hatanya gives 24 minutes after what he calls "Shkiya HaNirit". This is equated by Leo Levi to astronomical sunset (at sea level). However, other studies written after Leo Levi's book cite strong proof that the Baal Hatanya's "Shkiya Hanirit" occurs somewhat later than astronomical sunset (sea level) based on Responsa from the Geonic period. This would give Shkiya Hanirit a margin of up to 2 minutes after astronomical sunset, based on a passage in the Rambam, (which is consistent with a note of Rabbi Chaim of Volozhin, talmid of the Vilna Gaon).

Additionally, there are those who apply a shaa regila, a shaa zmamit or a shaa zmanit shel kayitz to tzeit hakochavim. This is most commonly applied to the 72 minute Rabbenu Tam shita.

Due to the law of tosefet Shabbat (adding to Shabbat), Shabbat and the holidays must be observed until some time after tzeit hakochavim (the end of bein hashmashot). According to Rav Shraya Deblitzki, this is done by waiting enough time after shkia to end up past tzeit hakochavim. Some poskim add a number of minutes to wait after tzeit hakochavim (typically 3 or 4). Which shita to use and how long to wait is a matter of local custom and should be checked with the appropriate local rabbinic authority.

In Eretz Yisrael, it is customary to wait until 3 small stars are visible in the night sky. According to Rav Y. M. Tucazinski, this corresponds to the center of the sun being 8.5 degrees below the horizon. The Sefardi community commonly observes 30 dakot zmaniot after shkia. Many communities observe some variation of the Rabbenu Tam shita.

Kaluach offers the following options:
• 3 small stars (center of the sun 8.5 degrees below horizon)
• Sefardim (30 proportional minutes after shkia)
• Rabbenu Tam (72 summer proportional minutes after shkia)
• custom options based on the position of the sun or on minutes

Other shitot that I've come across are:
• 3 medium stars (center of the sun 7.05 degrees below horizon)
• 45 dakot zmaniot (proportional minutes) after shkia
• 54 dakot zmaniot (proportional minutes) after shkia
The following are variations on the shita of the Rabbenu Tam:
• 72 dakot regilot (regular minutes) after shkia
• 72 dakot zmaniot (proportional minutes) after shkia
• 72 dakot zmaniot l'chumra (strict proportional minutes) after shkia
• center of the sun 16.1 degrees below the horizon

The Rabbenu Tam shita (and variants) is particularly prevelant outside of Eretz Yisrael. The 45 and 54 minute shitot are also commonly used. If you are not sure of the local minhag for your location (or if you are in a place that has no minhag), then it is recommended to use the shita of the Rabbenu Tam (the 72 minute shita). Waiting 72 dakot zmaniot l'chumra after shkia should take care of any safek (doubts).

David Kramer has suggested the inclusion of the "Egged tzeit Shabbat" (Egged is the major bus line in Israel). To the best of my knowledge, this is based solely on observation... If no one's looking, start the bus.

For the minor fasts (that is, all of the fasts excluding Yom Kippur and Tisha B'Av), the fast begins at alot hashachar. This means that one may rise early and eat before alot hashachar. There are those who take a lenient ruling on this and will use an earlier alot hashachar than usually used year round according to the zmanim shita for the user's location.

Fasts conclude at tzeit hakochavim. Except for Yom Kippur and Tisha B'Av, it is quite common to use a more lenient ending time. Kaluach allows changing the tzeit used for the end of a minor fast for those who prefer either a more lenient or more strict observance.

This is halachic midnight, the midpoint of the night between tzeit hakochavim and alot hashachar according to the Magen Avrahm, and sunset and sunrise according to the GR"A.