Sayyiduna Anas bin Malik (may Allah be pleased with him) reports this about the Prophet (peace and blessings be upon him): When he (peace and blessings be upon him) saw the new crescent moon, he would say: "May it be a crescent of goodness and right guidance; I believe in the One who created you and fashioned you well."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a narrator, Ahmad bin Isa al-Lakhmi, whom I do not know, and the remaining narrators of this report are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 17149
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«اخرجه الطبراني فى المعجم الاوسط (313) ، أخرجه المعجم الأوسط للطبراني برقم: 313»