Series: Daily Shiur

Venue: YU High School for Boys YU High School for Boys

Gemara:

Pesachim,  Shabbat 

Halacha:

Brit Milah,  Orach Chaim,  Science & Medicine,  Shabbat,  Yoreh Deah,  Zmanim 

Collections: R' Tanchum Cohen Pesachim 5781

References: Shabbat: 34B ,  Shabbat: 35A ,  Shabbat: 35B ,  Pesachim: 93B ,  Pesachim: 94A ,  Pesachim: 94B  

Description

Review of basic astronomical facts, of setira between Shabbas and Pesachim, and of Rabbeinu Tam's solution (2 meanings of 'shekia', shekia as a process). 4+ kushyos against Rabbeinu Tam, which lead into Gra's solution to setira (2 meanings of 'tzeis kochavim'). Geonim, rishonim and earlier acharonim who already disagreed with Rabbeinu Tam. The 3 types of 'dusk' (civil, nautical, astronomical) and their meanings and angles correspond to Gra-Tanya and 2 calculations of Rabbeinu Tam, and this dovetails elegantly with Gra's attack on Rabbeinu Tam from alos ha-shachar (kushya 4) and with the Rav applied to the Gra.