# Until what day of the month may Kiddush Levana be said-Part 2-Bedieved-How to calculate

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Until what day of the month may Kiddush Levana be said-Part 2-Bedieved & How to calculate

Initially one is to be very careful to recite Kiddush Levana prior to 14 days 18 hours and 396.5 chalakim past the Molad.[1] However, in the event that one already missed the time of the first/earliest opinion, one is to contact a Rav for direction as whether he may rely on one of the later approaches.[2] In all cases one may read the blessing from the Tur or Gemara.[3]

The three main opinions [for actual accurate calculation-see next step!]

Molad of Adar was on Monday evening, the 30th of Shevat, at 12:00 AM [Jerusalem time]:

1. First opinion of [14 days and 18:22 hours]: Kiddush Levana may be said until Monday evening, the 14th of Adar 1, until 6:22 p.m [in Jerusalem]. [In the Diaspora, it can only be said until this time arrives in Jerusalem.]
2. Second opinion [15 days]: Kiddush Levana may be said until Tuesday evening, the 15th of Adar 1, until 12:00 a.m [in Jerusalem]. [In the Diaspora, it can be said until this time arrives in Jerusalem.]
3. Third opinion [15 days 12 hrs 22 min]: Kiddush Levana may be said until Wednesday 12:22 p.m, the 15th of Adar 1, until 12:00 p.m [in Jerusalem]. [In the Diaspora, it can be said until this time arrives in Jerusalem.]

How to calculate the end time for Kiddush Levana:

1. Step 1-Molad time: Look up the exact time that the Molad occurred in Jerusalem [See https://www.torahcalc.com/molad/ to look up what time the Molad of the current month took place in Jerusalem].
2. Step 2-Detract solar versus watch time difference:[4] Detract 21 minutes from that time to supplement for the difference between the current watch time in Jerusalem versus the real solar time [Jerusalem is 21 minutes later than its real solar time.]
3. Step 3-Calculate to your local time zone: Calculate the exact time it was in your time zone when the Molad occurred in the above calculated time in Jerusalem.
4. Step 4-Add end time of Kiddush Levana: Add the end time of Kiddush Levana in accordance to whatever opinion you follow.

Example for one in New York:

1. Molad in Jerusalem occurred at 11:57 p.m on a Monday night, the 30th of Shevat
2. Minus 21 minutes = 11:36 p.m.
3. Seven hours back for New York time zone = 4:36 p.m, Monday afternoon, 29th of Shevat.
4. Add opinion of end time for Kiddush Levana, calculating it from 4:36 p.m. Thus, for example, according to the first opinion, add 14 days 18 hrs and 22 min, to the above time achieved in step 3. This would calculate the end time of Kiddush Levana in Jerusalem to be on Tuesday the 14th Adar 5:58 p.m. and in New York on Tuesday the 14th of Adar 9:58 a.m.

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[1] Kaf Hachaim 426:53 that so applies even for Sephardim that they should suspect for the opinion of Rama ibid

[2] M”B in Biur Halacha ibid concludes one may be lenient like Michaber ibid; Hiskashrus 961 writes [Vetzaruch Iyun as to his source] that one may say Kiddush Levana up to 18 hours past the time of the Rama [15 days 12 hours and 22 minutes from the Molad] as rules the Chasam Sofer, however he may not say it anymore once 18 hours have passed. In correspondence with Rav Ginzberg he wrote to me that this was the ruling of Rav Yaakov Landau, as was told to him by his son Rav Eliyahu Landau, that after 18 hours of the time of the Rama one may not be lenient to say it. This is despite the fact that the story mentioned above took place with Rav Yaakov Landau and he received a directive from the Rebbe Rashab to say Kiddush Levana on the night of the 20th. This story had been authenticated by the Rebbe Rayatz and was passed over his holy eyes prior to its publishing. Nevertheless, in actuality we are not lenient to rule this way. In an earlier volume of Hiskashrus [409] as well as in the glosses of Rav Raskin on the Siddur they wrote one may rely on the above story and recite Kiddush Levana even past the above time.

[3] Poskim stated in previous footnotes, see there. See glosses of Rav Raskin on Siddur who writes he recalls a directive of the Rebbe to say it from the Gemara when it is being said past the time.

Background: There are two important ways of describing time. “Clock time” is the artificial time that we use in everyday life to standardize our time measurements. It allows people in different locations to use the same time or to easily convert time from one location to another. “Local solar time” (or simply “solar time”) is the time according to the position of the sun in the sky relative to one specific location on the ground. In solar time, the sun is always due south (or north) at exactly noon. This means that someone a few miles east or west of you will realize a slightly different solar time than you, although your clock time is probably the same. For the purpose of calculating local solar time, clock time must modified to compensate for three things: (1) the relationship between the local time zone and the local longitude, (2) daylight savings time, and (3) the earth’s slightly-irregular motion around the sun (corrected for using the equation of time). Local solar time (LSoT) is calculated as follows: LSoT = LST + 4 minutes * (LL – LSTM) + ET Where: LST (local standard time) = Clock time, adjusted for daylight savings time if necessary. LL = The local longitude; positive = East, and negative = West. LSTM = The local standard time meridian, measured in degrees, which runs through the center of each time zone. It can be calculated by multiplying the differences in hours from Greenwich Mean Time by 15 degrees per hour. Positive = East, and negative = West. ET = The equation of time adjustment in minutes.

[5] Brought in Shemuos Vesippurim p. 182; This story was reviewed and authenticated by the Rebbe Rayatz. [See Kfar Chabad 986]

[6] This story took place in 1919, of which Motzei Shabbos was the 18th of Shevat. The original mistakenly states the 19th of Shevat.

[7] The story was written by Rav Yaakov Landau.

[8] Shemuos Vesipurim Vol. 2 p. 57