Sahih Muslim Book - 10, Hadith - 2092

وَحَدَّثَنَا مُحَمَّدُ بْنُ مِهْرَانَ الرَّازِىُّ حَدَّثَنَا الْوَلِيدُ بْنُ مُسْلِمٍ قَالَ قَالَ الأَوْزَاعِىُّ أَبُو عَمْرٍو وَغَيْرُهُ سَمِعْتُ ابْنَ شِهَابٍ الزُّهْرِىَّ يُخْبِرُ عَنْ عُرْوَةَ عَنْ عَائِشَةَ أَنَّ الشَّمْسَ خَسَفَتْ عَلَى عَهْدِ رَسُولِ اللَّهِ -صلى الله عليه وسلم- فَبَعَثَ مُنَادِيًا « الصَّلاَةَ جَامِعَةً ». فَاجْتَمَعُوا وَتَقَدَّمَ فَكَبَّرَ. وَصَلَّى أَرْبَعَ رَكَعَاتٍ فِى رَكْعَتَيْنِ وَأَرْبَعَ سَجَدَاتٍ.

It was narrated from 'Aishah that the sun was eclipsed at the time of the Messenger of Allah (s.a.w). He sent a caller calling: "The prayer is being assembled", and they gathered, and he went forward and said the Takbir, and prayed with four bowings and four prostrations in two Rak'ah.