Mu'ammal bin Isma'il (may Allah have mercy on him) narrates from Sufyan (may Allah have mercy on him), and in the hadith there are some additional words: Then he (peace and blessings be upon him) raised his head and prolonged the standing, until it was said: He (peace and blessings be upon him) will not bow. Then he (peace and blessings be upon him) performed a long bowing, until it was said: He (peace and blessings be upon him) will not raise his head from the bowing.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخسوف / 6313