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: Thursday 30th September 2027
Amavasya
Ghatasthapana
Shailputri Puja
Navratri color of the day – Yellow
Navratri Day 2: Friday 1st October 2027
Dwitiya
Chandra Darshan
Brahmacharini Puja
Navratri color of the day – Green
Navratri Day 3: Saturday 2nd October 2027
Tritiya
Sindoor Tritiya
Chandraghanta Puja
Navratri color of the day – Grey
Navratri Day 4: Sunday 3rd October 2027
Chaturthi
Kushmanda Puja
Varad Vinayaka Chauth
Navratri color of the day – Orange
Navratri Day 5: Monday 4th October 2027
Panchami
Upang Lalita Vrat
Skandamata Puja
Navratri color of the day – White
Navratri Day 6: Tuesday 5th October 2027
Shashthi
Katyayani Puja
Navratri color of the day – Red
Navratri Day 7: Wednesday 6th October 2027
Saptami
Saraswati Awahan
Kalaratri Puja
Navratri color of the day – Royal Blue
Navratri Day 8: Thursday 7th October 2027
Ashtami
Saraswati Puja
Durga Ashtami
Mahagauri Puja
Navratri color of the day – Pink
Navratri Day 9: Friday 8th October 2027
Ashtami
Sandhi Puja, Maha Navami
Navratri color of the day – Purple
Navratri Day 10: Saturday 9th October 2027
Navami
Ayudha Puja, Navami Homa
Navratri Parana
Vijayadashami
Navratri Day 11: Sunday 10th October 2027
Dashami
Durga Visarjan