Al-Kāfi - The Book of Prayer

Chapter: The Times of Maghrib and ‘Isha’ Salah (Prayer) َّدٍ عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ عَلِيِّ بْنِ الرَّيَّانِ قَالَ كَتَبْتُ إِلَيْهِ الرَّجُلُ يَكُونُ فِي الدَّارِ تَ٠ْنَعُهُ حِيطَانُهَا النَّظَرَ إِلَى حُ٠َغِيبِ الشَّفَقِ وَوَقْتِ صَلاَةِ الْعِشَاءِ الآخِرَةِ ٠َتَى يُصَلِّيهَا وَكَيْفَ يَصْنَعُ فَوَقَّعَ (عَلَيْهِ الْسَّلا٠) يُصَلِّيهَا إِذَا كَانَ عَلَى هَذِهِ الصِّفَةِ عِنْدَ قَصْرَةِ النُّجُو٠َغْرِبَ عِنْدَ اشْتِبَاكِهَا وَبَيَاضُ ٠ْسِ قَصْرَةُ النُّجُو٠ِ إِلَى بَيَانِهَا.

He (the Imam) (a.s.), signed the answer that said, ‘He performs it (al-‘Isha’) when on this side, stars appear and al-Maghrib when just few stars appear. The clarity of sunset is from the appearance of few stars until their clearly becoming visible.’” شهور - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (5/42))