Sandhi Puja is a very significant ritual during Navratri Puja. It is performed at the point when Ashtami Tithi ends and Navami Tithi begins. This is believed to be the moment when Devi Chamunda appeared to kill the demons Chanda and Munda.
Sandhi Puja is dominant for two Ghatis or approximately lasts for 48 minutes. It is possible that Sandhi Puja Muhurta occurs at any time of the day and Sandhi Puja should be done during that time only.
You might also refer the complete Shardiya Navratri Calendar and Durga Puja Calendar.
Navratri Day 1: Tuesday 19th September 2028
Pratipada
Ghatasthapana
Shailputri Puja
Navratri color of the day – Red
Navratri Day 2: Wednesday 20th September 2028
Dwitiya
Chandra Darshan
Brahmacharini Puja
Navratri color of the day – Royal Blue
Navratri Day 3: Thursday 21st September 2028
Tritiya
Sindoor Tritiya
Chandraghanta Puja
Varad Vinayaka Chauth
Navratri color of the day – Yellow
Navratri Day 4: Friday 22nd September 2028
Chaturthi
Kushmanda Puja
Upang Lalita Vrat
Navratri color of the day – Green
Navratri Day 5: Saturday 23rd September 2028
Panchami
Skandamata Puja
Navratri color of the day – Grey
Navratri Day 6: Sunday 24th September 2028
Shashthi
Katyayani Puja
Navratri color of the day – Orange
Navratri Day 7: Monday 25th September 2028
Saptami
Saraswati Awahan
Kalaratri Puja
Navratri color of the day – White
Navratri Day 8: Tuesday 26th September 2028
Ashtami
Saraswati Puja
Durga Ashtami
Mahagauri Puja
Sandhi Puja, Maha Navami
Navratri color of the day – Pink
Navratri Day 9: Wednesday 27th September 2028
Navami
Ayudha Puja, Navami Homa
Navratri Parana
Vijayadashami
Navratri color of the day – Sky Blue
Navratri Day 10: Thursday 28th September 2028
Dashami
Durga Visarjan