Sahih Muslim 908
Sahih Muslim · Book 10: The Book of Prayer - Eclipses · Those Who Say That He Prayed With Eight Bowings And Four Prostrations
Ibn 'Abbas reported:
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، حَدَّثَنَا إِسْمَاعِيلُ ابْنُ عُلَيَّةَ ، عَنْ سُفْيَانَ ، عَنْ حَبِيبٍ ، عَنْ طَاوُسٍ ، عَنِ ابْنِ عَبَّاسٍ ، قَالَ صَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم حِينَ كَسَفَتِ الشَّمْسُ ثَمَانَ رَكَعَاتٍ فِي أَرْبَعِ سَجَدَاتٍ . وَعَنْ عَلِيٍّ مِثْلُ ذَلِكَ .
When there was a solar eclipse the Messenger of Allah (way peace be upon him) observed eight ruku's and four prostrations (in two rak'ahs). This has been narrated by 'Ali also.