Narrated Ayyub: Umar bin Abd al-Aziz wrote (a letter) to the people of Basrah: It has reached us from the Messenger of Allah ﷺ, like the tradition narrated by Ibn Umar from the Prophet ﷺ. This version adds: The best calculation is that when we sight the moon of Sha'ban on such-and-such date, fasting will being on such-and-such dates, Allah willing, except they they sight the moon before that (date).
Hadith Referenceسنن ابي داود / كتاب الصيام / 2321
Hadith Gradingالألبانی:صحيح مقطوع | زبیر علی زئی:ضعيف, إسناده ضعيف, الحديث مرسل ولم يخبر الإمام عمر بن عبد العزيز ممن بلغه به, انوار الصحيفه، صفحه نمبر 87
Hadith Takhrij« تفرد بہ أبو داود، (تحفة الأشراف: 7536 و 19146) (صحیح) »
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues: The fundamental consideration and importance is given to sighting the moon, not merely to calculation.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 2321