What was the name of Galileo's daughter who became a nun?

Galileo's daughter who became a nun was Maria Celeste. She was born Virginia Galilei in Padua on 16 August 1600, the eldest of Galileo's three children with Marina Gamba.

Virginia entered the convent of San Matteo in Arcetri and took the veil on 4 October 1616. She adopted the religious name Maria Celeste, combining devotion to the Virgin Mary with a name reflecting her father's astronomical interests. Her sister Livia also became a nun, taking the name Sister Arcangela; this is the likeliest source of confusion between the two daughters.

Maria Celeste remained closely connected to Galileo from the convent. She helped manage convent affairs, prepared medicines, and wrote him warmly about household, financial, and family matters. Her surviving letters, written mainly from 1623 to 1633, provide an unusually intimate view of Galileo during the years surrounding his trial.

Maria Celeste died of dysentery on 2 April 1634, only months before Galileo's death. Thus, Virginia Galilei is her birth name, but Maria Celeste is the canonical name by which Galileo's nun daughter is known.