Magha Shukla Ashtami also called Bishma Ashtami is the death anniversary of Bhishma Pitamah, one of the most prominent characters of the great Indian epic, the Mahabharata.
History
Bhishma vowed for celibacy and followed it throughout his life. Due to his loyalty and devotion to his father, he was blessed with boon to choose the time of his death.
When he got injured in the battle of Mahabharata he didn't leave his body due to his boon. He waited for the auspicious moment to give up his body.
According to Hindu belief God Suryadev moves in South direction during half of year which is inauspicious period and all auspicious activities are postponed till Suryadev starts moving back in North direction.
Bhishma chose Magha Shukla Ashtami to give up his body and by this time Suryadev started moving back in North direction or Uttarayana.
Date and Tithi
Bhishma Ashtami 2022 Date: February 8, Tuesday.
Bhishma Ashtami 2022 Tithi Begins: February 08, 2022 6:16 AM.
Bhishma Ashtami 2022 Tithi Ends: February 09, 2022 8:31 AM.

Significance
On this day People do Ekodishta Shradhha for him. His Shradhha has been prescribed for those who have lost their father. However many believe that his Shradhha rituals can be performed by all irrespective of their father being alive or dead.
This day is celebrated with great dedication in ISKCON temples and Lord Vishnu temples all over the country.