Days are counted based on sunrise and sunset while 'Tithi' depends on the rising and setting of the moon. Sandhi Puja is performed counting 'Tithi'. Sasthi, Saptami, Nabami and Dashami pujas are performed after sunrise even if they fall in the previous evenings.
"Sandhi puja" is the End moment of Ashtami and the beginning of Nabami is the time for Sandhi Puja. At this time Devi Durga transformed into Devi Camunda to kill "Chando" and "Mundo", the two generals of
Mahishasura.
