The Origin of Announcing the Days of the New Moon in Synagogues
Yesterday, May 17, 2015, as on eleven of the twelve months of the year, many synagogues had their congregants rise as they followed the ancient custom to announce the appearance of the new moon during the Shabbat services prior to the onset of the new moon.
Why did this practice begin? Why do the synagogues announce the time that the new moon occurs in Jerusalem and not when it begins where the announcement is made? Why isn’t the announcement made before the new moon of the month when Rosh Hashana, the New Year holiday, occurs?
This ceremony began after the ancient procedure of using the testimony of witnesses to establish the beginning of a month; that is, after Jews began to use the calendar for this purpose rather than visual testimony, after the fourth century.
Since the ancient system was to announce the new moon so that people would know what day the elders or court established as the first day of the month, Jews decided to continue the traditional announcements even though they no longer had a useful purpose.
The question arose: where should the announcement be made and when? Jews decided that the most practical method was to make the statement on Shabbat at the synagogue service simply because this was the time and place where most Jews gathered.
The next question was whether people should be told of the new moon after the appearance of the month, like the ancient tradition, or before. Again, as a practical matter it was decided to make the proclamation before the onset of the new month. If the pronouncement were made after the onset of the month, it may not be made until a Sabbath six days after the new moon and it would serve no useful purpose at all. However, if the congregation were informed of the upcoming chodesh before the day(s) occurred, the announcement would alert the people that chodesh would be on a certain date and they should come to the synagogue to say the special prayers and listen to the Torah reading associated with chodesh.
Why does the announcement focus on Jerusalem, telling the time when the new moon is first seen there and not in the local community? Once it is realized that the ceremony is designed to recall the ancient practice and the ancient practice was to announce the new moon in Jerusalem, it is clear why we continue to refer to Jerusalem today.
Why are some of the new moon celebrations, but not all of them, two days when the month begins on only one day? I’ll talk about the extra day later this week. The truth is not what people think.
Why is there a practice to make no announcement to alert people when the month of Tishrei, the month of the holiday of Rosh Hashanah, begins? Some people insist that no announcement is made to confuse Satan who, without the announcement, would not know when Rosh Hashanah begins and would not be able to bring evil reports to God in a timely fashion. Many Jews believe that their future is determined on Rosh Hashanah and want to do all they could to assure a favorable divine decision. The superstition about Satan imagines that Satan is quite a dupe and also that God can be persuaded to harm Jews based on the eloquence of the demon.
Once we remember that the present synagogue proclamation recalls the ancient pronouncement made by elders or a court, we realize that the answer is simple: there was no rush to publicize the first day of Tishrei in ancient times because the ancients had declared Yom Teruah, later called Rosh Hashanah, a two-day holiday, even though it is only a single day in the Bible, to assure that the sacrifices that the Torah mandates for the day will be brought.
Thus, the declarations of the new moon in synagogues today, including the practice not to do so before Tishrei, are reminders of the pre-calendar procedures of ancient Jewry.
 The biblical name for the day of the new moon is chodesh, literally, “new.” The term rosh chodesh, which means the head new month, was used in the Bible to refer to the first new month of the year that occurred on the first month Nissan. Later, because of a misunderstanding, Jews called all starts of months rosh chodesh.