Q. Can you explain Kiddush L’vanah (saying a prayer when we see the new moon)?
These days we work out the date of Rosh Chodesh by means of mathematical calculations, and on the previous Shabbat we make an appropriate announcement during the services (except for the month of Tishri).
However, there is still a way in which we take note of the actual arrival of the new moon. This is Kiddush L’vanah, which is a combination of verses, prayers and blessings, recited out of doors early in the new month.
One view is that it should be said as soon as the new moon is visible. Most authorities require us to wait until the moon is sufficiently bright to be able to affect the earth. Kiddush L’vanah is usually said on Saturday evening when we are still dressed for Shabbat.
The prayers said emphasise not only that the moon is seen but that it is evidence of the creative activity of the Almighty. By gazing at the heavenly bodies we know there is a God and we feel a sense of privilege at beholding His handiwork.