Musannaf Ibn Abi Shayba 3:851

Ghundar narrated to us, from Shu'bah, from Qatadah, who said: I heard Abu Ayyub narrating from Abdullah ibn Amr, who said: The time for Dhuhr is as long as the time for Asr has not arrived. The time for Asr is as long as the sun has not turned yellow. The time for Maghrib is as long as the light of the twilight has not fallen. The time for Isha is until the middle of the night. The time for Subh (Fajr) is as long as the sun has not risen.