(4) باب ذِكْرِ مَنْ قَالَ إِنَّهُ رَكَعَ ثَمَانَ رَكَعَاتٍ فِي أَرْبَعِ سَجَدَاتٍ
Ibn 'Abbas reported:
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.
Reference: Sahih Muslim 908
In-book reference: Book 10, Hadith 20
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1984