Hadith.1932 - Amru ibn Shimr narrated from Jabir, from Abu Ja'far عليه السلام, who said that the Messenger of Allah سبحانه وتعالى (peace be upon him and his family) said:
"When the disk of the sun disappears, the fasting person may break their fast, and the time for prayer begins."
My father—may Allah سبحانه وتعالى be pleased with him—in his letter to me said: It is permissible for you to break your fast when three stars appear, rising with the sunset.
This is also narrated by Aban from Zurara, from Abu Ja'far عليه السلام.