Bein HaShemashot - Igrot Moshe Orach Chaim 4:62

This teshuva, written in 1979 to Rav Moshe's son-in-law Rav Moshe Dovid Tendler, is concerned primarily with the issue of the timing of sunset, bein ha-shemashot, and tzeit ha-kochavim. Rav Moshe's main point in the first half of the teshuva is to establish that in New York, and in fact in all of America (certainly in the area around NYC), bein ha-shemashot can be said to last 50 minutes. This is a departure from the 72 minutes or more (perhaps as much as 96 minutes) that was assumed in Europe, and Rav Moshe's rationale is that the difference is based on latitude, meaning that the time between sunset and darkness differs as a city is closer to or further from the equator. As such, in America Shabbat can be declared over 50 minutes after sunset.

The rest of the teshuva discusses several ramifications of this approach, including:

• Lighting Chanukah candles on Friday night (should be lit before Shabbat candles, based on how long tosefet Shabbat is in America)


• Amira l'akum and sha'at hadechak - if something needs to be done after sunset on Friday and it falls into one of these two categories, it can be done until 40 minutes after sunset. On Saturday night, there is a dispute whether such things can be done 10 minutes or 40 minutes (Magen Avraham) after Shabbat.


• Brit Mila for a child born during bein ha-shemashot (long discussion)


• A woman who cannot do a hefsek tahara for the entire bein ha-shemashot should do one for at least 9 minutes (this leniency is based on the existence of a sfek sfeika)


• A person who has a hard time fasting can end his fast after 41 minutes after sunset if the fast is d'rabbanan. If it is Ta'anit Esther, such a person can even eat before hearing Megilla.