Angarika Chaturthi , Angaraka Chaturhti
The reason for Sankashti Chaturthi being known as Angarika Chaturthi is explained by the story below. The connectivity between a Tuesday and Ganesha is explained below.
The birth of Bhauma
Once in Kailash, Lord Shiva was immersed in great Penance (Tapasya). While in penance, three drops of sweat fell from his fore head on the ground. The sweat drops transformed into child with red complexion as if a burning fire and with four arms.
The Earth gave this kid to Sage Bhardwaja. As he was given by Earth he was named as Bhauma, “The son of Earth”.
When Bhauma was in his teens, Sage Bhradwaja preached him the “Ganesh Mantra” and also explained the way in which one should recite the same. Sage Bhardwaja advised Bhauma to go to the banks of Narmada and perform Penance or Tapasya to seek the blessings of Lord Ganesha.
Bhauma, as suggested by his father, performed great penance for Lord Ganesha, reciting the Ganesh Mantra. Lord Ganesha after few years, pleased with the penance appeared to Bhauma on the fourth day of Krishna Paksha Magh Masam of Telugu calendar, i.e on the fourth day of waning phase of the moon in the month of Magha.
Lord Ganesha, made Bhauma the head of Mangala Loka. Lord Ganesha also said that Bhauma would become famous by the name of Angaraka. Lord Ganesha further added that, those who observe the Sankashti Chaturthi Vrat on a Mangalavara or Tuesday would be blessed with multi fold virtue than performing on a normal Sankashti Chaturthi.Lord Ganesha also declared that a Sankashthi Chaturthi which would fall on a Mangala Vara or Tuesday would be known as Angarika Chaturthi or Angaraka Chaturthi.