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Reference of Measurements in Halacha: Difference between revisions
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* Another means for calculation, which has only recently been implemented, is to compare the level of brightness by using the relative position of the sun. For instance, it has been determined that 60 minutes before sunrise on a perfect day in Jerusalem the sun is 12.9 degrees below the horizon. Therefore, if one wanted to find the equivalent time anywhere in the world during any season, he would simply determine at what time the sun will be 12.9 degrees below the horizon in that locale on that day and that would be the extrapolated Meshiyakir.</ref> Thus, according to the commonly accepted opinion that Meshiyakir is between 50 and 60 minutes before sunrise in Jerusalem - In New York, depending on the time of the year, it could be anywhere from 56-73 minutes before sunrise.<ref>MyZmanim.com. These figures are determined using MyZmanim’s earliest published position of 11.5 degrees below the horizon. Unfortunately, MyZmanim.com only offers calculations based upon 10.2 degrees, 11 degrees, and 11.5 degrees but not 12.9 degrees. It is unfortunate because 12.9 degrees correlates to Rav Tukaczinsky’s 60 minutes before sunrise which, although is a very lenient position is also well collaborated and accepted.</ref> | * Another means for calculation, which has only recently been implemented, is to compare the level of brightness by using the relative position of the sun. For instance, it has been determined that 60 minutes before sunrise on a perfect day in Jerusalem the sun is 12.9 degrees below the horizon. Therefore, if one wanted to find the equivalent time anywhere in the world during any season, he would simply determine at what time the sun will be 12.9 degrees below the horizon in that locale on that day and that would be the extrapolated Meshiyakir.</ref> Thus, according to the commonly accepted opinion that Meshiyakir is between 50 and 60 minutes before sunrise in Jerusalem - In New York, depending on the time of the year, it could be anywhere from 56-73 minutes before sunrise.<ref>MyZmanim.com. These figures are determined using MyZmanim’s earliest published position of 11.5 degrees below the horizon. Unfortunately, MyZmanim.com only offers calculations based upon 10.2 degrees, 11 degrees, and 11.5 degrees but not 12.9 degrees. It is unfortunate because 12.9 degrees correlates to Rav Tukaczinsky’s 60 minutes before sunrise which, although is a very lenient position is also well collaborated and accepted.</ref> | ||
==Olot HaShachar== | ==Olot HaShachar== | ||
# Many rishonim hold that Olot HaShachar is 72 minutes before sunrise on a perfect day in Jerusalem which is equivalent to when the sun is 16 degrees below the horizon for everywhere in the world, however, others hold that Olot HaShachar is 90 minutes on a perfect day which is 19.78 degrees below the horizon. <ref>Sefer Zmanim KeHilchatam (Rabbi Berstein, pg 347) writes that 72 minutes on a perfect day in Jerusalem is equal to when the sun is 16 degrees below the horizon and 90 minutes is equal to 19.78 degrees below the horizon. He personally rules that one should be strict for both of these opinions for Deoritta halachas and those derabbanan halachas where safek is lechumra. He tries to prove that this is the opinion of the Mishna Brurah (92:3, Biur Halacha 163:1 D"H Berachok). However, he totally rejects the opinion that Olot HaShachar is 120 minutes before sunrise.</ref> | # Many rishonim hold that Olot HaShachar is 72 minutes before sunrise on a perfect day in Jerusalem which is equivalent to when the sun is 16 degrees below the horizon for everywhere in the world, however, others hold that Olot HaShachar is 90 minutes on a perfect day which is 19.78 degrees below the horizon. <ref>Sefer Zmanim KeHilchatam (Rabbi Berstein, pg 347) writes that 72 minutes on a perfect day in Jerusalem is equal to when the sun is 16 degrees below the horizon and 90 minutes is equal to 19.78 degrees below the horizon. He personally rules that one should be strict for both of these opinions for Deoritta halachas and those derabbanan halachas where safek is lechumra. He tries to prove that this is the opinion of the Mishna Brurah (92:3, Biur Halacha 163:1 D"H Berachok). However, he totally rejects the opinion that Olot HaShachar is 120 minutes before sunrise. He also quotes Rabbi Tukachinsky who held like the opinion of 90 minutes. </ref> | ||
==Shaot Zmaniot== | |||
# Some calculate the hours by dividing the time from Olot HaShachar until Tzet HaChochavim into 12 parts (Magan Avraham) while others divide the time from sunrise until sunset (Gra). <ref>Rabbi Yechiel Michel Tukachinsky in Sefer Eretz Yisrael (pg 18#3) writes that the minhag of Israel is to follow the magen avraham and only under pressure may one rely on the gra. </ref> | |||
==Related pages== | ==Related pages== | ||
[[Shiur of K'zayis]] | [[Shiur of K'zayis]] | ||
==References== | ==References== | ||
<references/> | <references/> | ||
