SEFIRAT HAOMER: More on the Mitzva of Counting the Omer

The days of the Omer need to be counted at night. As you already probably know, for us the new day starts at night. Like Shabbat which starts Friday night.

At what precise time the new day starts is a controversial complicated technical Halakhic matter. But very briefly: there are two possible astronomic indicators for the new day:
1. Sunset. 2. The appearance of stars in the dark sky. All Rabbis agree that before sunset it is still considered day # 1 and after the stars are visible it is considered day #2. The time in between sunset and the stars (twilight zone or ben hashemashot) fluctuates between 15 min (13 ½ to be precise!) to 30 minutes or more depending on many variables (geographic location, year’s season, etc.). Regarding Shabbat, for example, we take the stringiest stand: we receive Shabbat before sunset and we end Shabbat the next day, after the stars are visible.

Regarding the counting of the Omer, according to Rabbi Eliyahu Ben Hayim the starting time to count the Omer will be 13 ½ minutes after sunset. For a Minyan one could be more lenient but never before sunset.

Children, although formally exempt from the Mitzvah of counting the days of the Omer until Bar or Bat Mitzva, should be encouraged to count every night including the recitation of the berakha, because the rules of berakha lebatala (saying a formal blessing unnecessarily) does not apply for children.