Musnad Ahmad 5:685

'Abdullah narrated to us, 'Abd al-Rahman 'Abdullah ibn 'Umar narrated to me, al-Muharibi narrated to us, from Fudayl ibn Marzuq, from Abu Ishaq, from 'Asim ibn Damrah, from 'Ali, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) prayed the Duha prayer when the sun was in its position from the east, [corresponding to] its position from the west at the time of the 'Asr prayer."