I spent a night with my maternal aunt Maymunah. The Prophet ﷺ got up to pray at night. He prayed thirteen rak'ahs including two rak'ahs of the dawn prayer. I guessed that he stood in every rak'ah as long as one could recite Surah al-Muzzammil (73).  

بِتُّ عِنْدَ خَالَتِي مَيْمُونَةَ فَقَامَ النَّبِيُّ ﷺ يُصَلِّي مِنَ اللَّيْلِ فَصَلَّى ثَلاَثَ عَشْرَةَ رَكْعَةً مِنْهَا رَكْعَتَا الْفَجْرِ حَزَرْتُ قِيَامَهُ فِي كُلِّ رَكْعَةٍ بِقَدْرِ { يَا أَيُّهَا الْمُزَّمِّلُ } لَمْ يَقُلْ نُوحٌ مِنْهَا رَكْعَتَا الْفَجْرِ  

[Machine] I was at the house of Maymuna, and the Prophet ﷺ stood up to pray at night. I joined him on his left side, and he held my hand, placing me on his right. Then he prayed thirteen rak'ahs, and I estimated the length of his standing in each rak'ah, saying, "O you, wrapped in garments!"  

كُنْتُ فِي بَيْتِ مَيْمُونَةَ فَقَامَ النَّبِيُّ ﷺ يُصَلِّي مِنَ اللَّيْلِ فَقُمْتُ مَعَهُ عَلَى يَسَارِهِ فَأَخَذَ بِيَدِي فَجَعَلَنِي عَنْ يَمِينِهِ ثُمَّ صَلَّى ثَلَاثَ عَشْرَةَ رَكْعَةً حَزَرْتُ قَدْرَ قِيَامِهِ فِي كُلِّ رَكْعَةٍ قَدْرَ يَا أَيُّهَا الْمُزَّمِّلُ  

[Machine] I was at my aunt Maymuna's house. The Prophet ﷺ got up to pray at night, so I stood to his left. He took my hand and placed me on his right. Then he prayed thirteen units of prayer. I observed his standing in each unit just as O' Enveloped One.  

كُنْتُ فِي بَيْتِ خَالَتِي مَيْمُونَةَ «فَقَامَ النَّبِيُّ ﷺ يُصَلِّي مِنَ اللَّيْلِ فَقُمْتُ عَنْ يَسَارِهِ فَأَخَذَ بِيَدِي فَجَعَلَنِي عَنْ يَمِينِهِ ثُمَّ صَلَّى ثَلَاثَ عَشْرَةَ رَكْعَةً حَرَزْتُ قِيَامَهُ فِي كُلِّ رَكْعَةٍ قَدْرَ يَا أَيُّهَا الْمُزَّمِّلُ»  

[Machine] I was at the house of Maymuna when the Prophet ﷺ stood up to pray at night. I stood up with him on his left side, and he took my hand and placed me on his right side. Then he prayed thirteen units of prayer, and I guessed the length of his standing in each unit, O you (Prophet) wrapped in garments.  

كُنْتُ فِي بَيْتِ مَيْمُونَةَ فَقَامَ النَّبِيُّ ﷺ «يُصَلِّي مِنَ اللَّيْلِ فَقُمْتُ مَعَهُ عَلَى يَسَارِهِ فَأَخَذَ بِيَدِي فَجَعَلَنِي عَنْ يَمِينِهِ ثُمَّ صَلَّى ثَلَاثَ عَشْرَةَ رَكْعَةً حَزَرْتُ قَدْرَ قِيَامِهِ فِي كُلِّ رَكْعَةٍ يَا أَيُّهَا الْمُزَّمِّلُ»  

[Machine] I stayed at the house of Maymuna, so the Prophet ﷺ got up to pray in the night. I stood on his left side and he held my hand and placed me on his right. Then he prayed thirteen rak'ahs, and I estimated the amount of time he stood in each rak'ah. In each rak'ah he recited, "O you wrapped in garments" [Surah Al-Muzzammil, verse 1].  

بِتُّ فِي بَيْتِ مَيْمُونَةَ فَقَامَ النَّبِيُّ ﷺ يُصَلِّي مِنَ اللَّيْلِ فَقُمْتُ مَعَهُ عَنْ يَسَارِهِ فَأَخَذَ بِيَدِي فَجَعَلَنِي عَنْ يَمِينِهِ ثُمَّ صَلَّى ثَلَاثَ عَشْرَةَ رَكْعَةً حَزَرْتُ قَدْرَ قِيَامِهِ فِي كُلِّ رَكْعَةٍ {يَا أَيُّهَا الْمُزَّمِّلُ} [المزمل 1]  

"كُنْتُ فِى بَيْتِ مَيْمُونَةَ، فَقَامَ النَّبِىُّ ﷺ يُصَلِّى مِنَ اللَّيْلِ، فَقُمْتُ مَعَهُ عَلَى يَسَارهِ، فَأَخَذَ بيَدى فَجَعَلَنى عَنْ يَمينهِ، ثُمَّ صَلَّى ثَلاثَ عَشْرَةَ رَكْعَةً، حَزَرْتُ قيَامَهُ في كُلِّ ركْعَةٍ قَدْرَ {يأَيُّهَا الْمُزَّمِّلُ} ".  

"كُنْتُ فِى بَيْتِ مَيْمُونَةَ فَقَامَ النَّبِيُّ ﷺ مِنَ الَّليْلِ، فَقُمْتُ مَعَهُ عَلَى يَسَارِهِ، فَأَخَذَ بِيَدِى، فَجَعَلَنِى عَنْ يَمِينِهِ، ثُمَّ صَلَّى ثَلاَثَ عَشْرَةَ رَكْعَةً، حَزَرْتُ (*) قِيَامَهُ فِى كُلِّ رَكْعَةٍ قَدْرَ: يَا أَيُّهَا الْمُزَّمِّلُ".