Why are both Ashtami and Navami occuring on October 19?

Ashtami and Navami, two key days of Navratri, are being observed on October 19 due to the Hindu lunar calendar. Hindu festivals follow tithis, or lunar days, which can be shorter or longer than a solar day and can begin at any hour. Several panchangs place end of Ashtami around 10:50 am on October 19 and Navami begins right after.