Last week we explained the importance of Berit Mila, the signal of Jewish identity of a Jewish male, in its reproductive organ. (The Jewish female, says rabbi Melamed, is herself --or her womb-- the symbol of Jewish identity. Because Jewishness is transmitted/"reproduced" exclusively via the mother :only when the mother is Jewish, the baby is Jewish as well).
The Berit Mila is performed eight days after the baby is born. It is critical to know at what time exactly the baby was born. Illustration: Sunset (sheqia) in NYC is today at 8.13PM. If a baby is born before 8.13 PM the brit Mila will be done next Monday. But if is born after 8.42PM--(nighttime, 3 stars in NYC, for most opinions) the Berit Mila will be next Tuesday. Now, if the baby was born in between sunset and nightfall (twilight, ben hashemashot), a Rabbi or an expert Mohel should be consulted to establish if the Berit Mila should be performed Monday or Tuesday.
The Berit Mila ceremony should take place only during daytime, since the Torah specifically indicated bayom hashemini,.. "on the eighth day" (=daytime). Even when the Berit Mila is postponed, and not done on the eighth day, it should be done during daytime.
Ideally, the ceremony should be scheduled early in the morning, after Shacharit service. Jewish tradition says that one should be eager to perform a Mitzvah (zerizim makdimim laMitzvot). This is the standard Sephardic Minhag. Other Rabbis would say that the Berit Mila could be done in the afternoon, anytime before sundown, if more people -especially close relatives- will be able to attend the ceremony.