Start of month of Av on the Hebrew calendar. Av (???) is the 5th month of the Hebrew year, has 30 days, and corresponds to July or August on the Gregorian calendar. ????? ???????, transliterated Rosh Chodesh or Rosh Hodesh, is a minor holiday that occurs at the beginning of every month in the Hebrew calendar. It is marked by the birth of a new moon

Torah: Numbers 28:1-15

https://hebcal.com/h/rosh-chodesh-av-2028?uc=ical-jewish-holidays-all