Ashtami, Navami in October 2026: why Sandhi Puja has two times, three hours apart

For people searching for Ashtami and Navami in October 2026, the Bengali almanacs used for Durga Puja put Maha Ashtami on Monday, October 19, 2026, Maha Navami on Tuesday, October 20, and Vijaya Dashami on Wednesday, October 21. The most precisely timed ritual of the festival, Sandhi Puja, falls on the morning of October 19, but it has two different timings in Kolkata depending on which almanac a puja committee follows. The Vishuddha Siddhanta almanac gives 10:29 am to 11:17 am, with the exact junction at 10:53 am, while the older Surya Siddhanta-based tradition followed by the Gupta Press almanac gives 7:25 am to 8:13 am, with the junction at 7:49 am. The gap of about three hours comes from two different ways of calculating the positions of the Sun, Moon and planets.

Sandhi Puja is performed at the meeting point of two lunar days, so its timing depends entirely on when the eighth tithi of the waxing Moon ends and the ninth begins. A tithi is a lunar day, and the published timings show it does not begin or end at midnight: this year the junction falls in the middle of the morning. Getting that moment right needs an accurate model of the heavens, and Bengal's almanac makers have been split on that model for more than a century.

One school, represented by the Gupta Press almanac and others such as P. M. Bagchi, follows the older method. Its calculations rest on the Surya Siddhanta, an astronomical treatise about 1,500 years old, as applied in the 16th-century work of the scholar Raghunandan. The other school, the Vishuddha Siddhanta Panjika, began in 1890 with an amendment of the planetary positions, after astronomers and scholars found discrepancies in the older system. Its first editor was the mathematician Madhab Chandra Chattopadhyay, and it is described as the observation-based, or drik, school.

The split is not only academic. In 2005 the two systems produced two different sets of dates for Durga Puja itself. Belur Math follows the Vishuddha Siddhanta almanac, while many community pujas have stayed with the Gupta Press almanac because of its popularity. This year the dates agree, but the Sandhi Puja timings still differ by about three hours.

Short-term: Puja committees, priests and families will hold Sandhi Puja at the time given by the almanac they follow, so neighbouring pandals in Kolkata and Dhaka may perform it hours apart on the same morning. Devotees planning to attend should check which almanac their local puja uses.

Long-term: The two timings are a living example of how India's traditional astronomy has been revised over time. The Surya Siddhanta tradition preserves an old method; the 1890 reform shows Indian scholars correcting it against observation. Both remain in use, which makes the Bengali almanac one of the few places where the history of Indian astronomy shapes a public ritual every year.

Who is affected: Durga Puja organisers, priests and devotees in West Bengal, Bangladesh and the wider Bengali diaspora, and anyone who relies on a panjika for festival timings.

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