´It was narrated that An-Nu'man bin Bashir said:` "I am the most knowledgeable of people about the time of the 'Isha' prayer. The Prophet (ﷺ) used to pray it when the moon set on the third night of the month."
Hadith ReferenceSunan an-Nasa'i / The Book of the Times (of Prayer) / Hadith: 529