Abdullah bin Safwan says that I saw Ibn Abbas (may Allah be pleased with them) perform two rak'ahs in the case of a solar and lunar eclipse, and there were two bowings (ruku) in each rak'ah.
Hadith Referenceمسند الإمام الشافعي / كتاب الكسوف / 547
Hadith Takhrijاسناده ضعيف لضعف شیخ الشافعي أخرجه البيهقي : 3/ 328 ، 342 وفي المعرفة السنن والآثار (1977)۔