Shibak narrates from Ibrahim that he said: Sayyiduna Umar (may Allah be pleased with him) wrote to Utbah bin Farqad: "When you see the new moon in the daytime before the sun passes the meridian, on the completion of thirty days, then break your fast; and when you see it after the sun has passed the meridian, then do not break your fast, and remain fasting."
Ibrahim al-Nakha'i narrated it munqati' (with a broken chain), and the hadith of Abu Wa'il is more authentic than it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 7985