Final answer:
Ismailis celebrate the night of the new moon every month, known as Chand Raat, which differs from other Islamic holy nights like Laylat al-Baraat, Laylat al-Qadr, and Laylat al-Milad.
Step-by-step explanation:
The night of the new moon that Ismailis celebrate each month is called Chand Raat. This term is derived from Urdu and translates to 'night of the moon'. Chand Raat is not to be mistaken with the other Islamic holy nights such as Laylat al-Baraat, Laylat al-Qadr, or Laylat al-Milad, which have their unique significance and place within Islamic culture and religious practices. The Islamic calendar, which Muslims follow, is an uncorrected lunar calendar leading to their holidays shifting approximately 11 days earlier each year in relation to the Gregorian calendar. This movement through the seasons is intentional, allowing Islamic holidays to occur independently of any other religious calendar.