Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that a man came to the Prophet (peace and blessings be upon him), and he narrated the hadith, in which it says: "When you have prayed the Fajr prayer, refrain from prayer until the sun has risen high, for it rises between the two horns of Satan. Then prayer is witnessed and attended (by the angels) and accepted, until midday."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة العيدين / 6151