It is narrated from Hazrat Nu'man (may Allah be pleased with him) that I know the time of the 'Isha prayer of the Noble Prophet (peace and blessings be upon him) better than anyone else. The Noble Prophet (peace and blessings be upon him) used to offer this prayer on the third night at the beginning of the month after the moon had set.
Hadith Referenceمسند احمد / أول مسند الكوفيين / 18377
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد اختلف فيه