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Reference of Measurements in Halacha: Difference between revisions
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Reference of Measurements in Halacha (view source)
Revision as of 13:58, 16 July 2024
, 16 July 2024→Degrees
(→Degrees: You may want to add what the Sephardi gedolim say about this. I think these tidbits of information help get a better understanding of what is going on here.) |
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# The time of ''alot hashachar'' refers to an astronomical event in which the light from the sun first becomes visible on the horizon.<ref>Biur Halacha 89:1 quotes ''poskim'' who write that it is when the whole eastern horizon becomes light. This does not make a difference in our discussion.</ref> The sun's rays become visible when the sun is a certain number of degrees below the horizon. The timing of this varies depending on the locale and the time of year. Thus, many ''poskim'' write, that ''alot'' cannot be calculated by time; rather, it must be based on the position of the sun below the horizon. The first light always appears when the sun is a certain number of degrees below the horizon. | # The time of ''alot hashachar'' refers to an astronomical event in which the light from the sun first becomes visible on the horizon.<ref>Biur Halacha 89:1 quotes ''poskim'' who write that it is when the whole eastern horizon becomes light. This does not make a difference in our discussion.</ref> The sun's rays become visible when the sun is a certain number of degrees below the horizon. The timing of this varies depending on the locale and the time of year. Thus, many ''poskim'' write, that ''alot'' cannot be calculated by time; rather, it must be based on the position of the sun below the horizon. The first light always appears when the sun is a certain number of degrees below the horizon. | ||
# According to this, the measurements given in ''mil'' actually refer to degrees. | # According to this, the measurements given in ''mil'' actually refer to degrees. In other words, when the ''poskim'' write that ''alot'' occurs 72 minutes before sunrise they do not mean to say that the first light appears 72 minutes before sunrise in every locale, on every day of the year. Rather, they are discussing the time of ''alot'' in Israel or Bavel on the equinox at which time the sun is approximately 16.1º below the horizon. By converting ''mil'' into degrees, we are merely conveying the "72 minutes" to apply them to any locale and for any time of the year.<ref>Dvar Yom (English) Chap.7, in paragraph 24 he writes that even those who offer other methods for calculating ''alot'', such as ''shaot zmaniot'', agree that when light is visible on the horizon it is ''alot hashachar.'' According to this, one relying on ''shaot zmaniot'' must be stringent using both degrees and ''shaot zmaniot.'' For example, on January 1st in Jerusalem, 16.1 degrees is 5:22, and 72 minutes ''shaot zmaniot'' is 5:38 (see Zemanei Halacha pg.34). If one is fasting and would like to eat before the fast, they would have to stop eating at 5:22 because at that time light is visible on the horizon. However, if one would like to say Hallel one would have to wait until 5:38 which is the halachic time of ''alot'' using ''shaot zmaniot.'' | ||
*Dvar Yom Chap. 7 footnote 58 writes that some people mistakenly think that measuring by degrees is a new invention. How is it possible that 400 years ago they were able to measure the position of the sun below the horizon? He explains that degrees is a way of calculating when the first light will appear. It is easy to understand how they calculated ''alot'' in the olden days - they watched for the first light to appear. </ref> | *Dvar Yom Chap. 7 footnote 58 writes that some people mistakenly think that measuring by degrees is a new invention. How is it possible that 400 years ago they were able to measure the position of the sun below the horizon? He explains that degrees is a way of calculating when the first light will appear. It is easy to understand how they calculated ''alot'' in the olden days - they watched for the first light to appear. </ref> | ||
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##72 minutes fixed before Netz.<ref>Zmanei Hahalacha Lmaaseh p. 18 writes that 72 minutes fixed is based on the rishonim that a mil is 18 minutes and there is 4 mil between Alot and Netz.</ref> | ##72 minutes fixed before Netz.<ref>Zmanei Hahalacha Lmaaseh p. 18 writes that 72 minutes fixed is based on the rishonim that a mil is 18 minutes and there is 4 mil between Alot and Netz.</ref> | ||
=== | ===Misheyakir=== | ||
#There is a wide range of opinions precisely when Misheyakir occurs in Jerusalem on a perfect day, when there is exactly 12 daylight hours and every seasonal hour consists of 60 minutes. The three opinions include: 35 minutes before sunrise,<ref>Rav Moshe Feinstein in Le-Torah ve-Hora'ah Vol. 3:7 and in Iggeros Moshe OC 4:6 holds of 35 minutes. Rav Yaakov Kamenetsky in Emes liyaakov OC 58:1 rules that it is 36 minutes before sunrise. Zmanei Halacha LeMaaseh (pg 19) holds of 40 minutes before sunrise. </ref> 60 minutes before sunrise,<ref>Rav Tukaczinsky in Sefer Eretz Yisrael 1:4 (pg 18), Kaf HaChaim 18:18, Sh"t Binyan Tzion 2:16 hold of 60 minutes before sunrise. Nivreshet (vol 1, pg 43) holds of 52 minutes.</ref> and 66 minutes before sunrise.<ref>Rav Ovadya Yoseh in Yechave Daat 2:8</ref> | #There is a wide range of opinions precisely when Misheyakir occurs in Jerusalem on a perfect day, when there is exactly 12 daylight hours and every seasonal hour consists of 60 minutes. The three opinions include: 35 minutes before sunrise,<ref>Rav Moshe Feinstein in Le-Torah ve-Hora'ah Vol. 3:7 and in Iggeros Moshe OC 4:6 holds of 35 minutes. Rav Yaakov Kamenetsky in Emes liyaakov OC 58:1 rules that it is 36 minutes before sunrise. Zmanei Halacha LeMaaseh (pg 19) holds of 40 minutes before sunrise. </ref> 60 minutes before sunrise,<ref>Rav Tukaczinsky in Sefer Eretz Yisrael 1:4 (pg 18), Kaf HaChaim 18:18, Sh"t Binyan Tzion 2:16 hold of 60 minutes before sunrise. Nivreshet (vol 1, pg 43) holds of 52 minutes.</ref> and 66 minutes before sunrise.<ref>Rav Ovadya Yoseh in Yechave Daat 2:8</ref> | ||
