The five-day celebration is observed every year in early autumn after the conclusion of the summer harvest, coincides with the new moon ("amāvasyā") and is deemed the darkest night of the Hindu lunisolar calendar. The festivities begin two days before "amāvasyā", on Dhanteras, and extend two days after, on the second day of the month of Kartik. (According to Indologist Constance Jones, this night ends the lunar month of Ashwin and starts the month of Kartik – but see this note and Amanta and Purnima systems.) The darkest night is the apex of the celebration and coincides with the second half of October or early November in the Gregorian calendar.