Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
nasai-kubra:1544Muḥammad b. ʿAbd al-Aʿlá > Khālid > Shuʿbah > Abū Ṣadaqah > Anas

[Machine] The Messenger of Allah ﷺ used to pray the last Isha' prayer when the twilight disappears, then he would pray Fajr until daybreak.  

الكبرى للنسائي:١٥٤٤أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الْأَعْلَى قَالَ حَدَّثَنَا خَالِدٌ عَنْ شُعْبَةَ عَنْ أَبِي صَدَقَةَ عَنْ أَنَسٍ قَالَ

كَانَ رَسُولُ اللهِ ﷺ يُصَلِّي الْعِشَاءَ الْآخِرَةَ إِذَا غَابَ الشَّفَقُ ثُمَّ قَالَ عَلَى إِثْرِهِ وَيُصَلِّي الْفَجْرَ إِلَى أَنْ يَنْفَسِحَ الْبَصَرُ