Steele and Annette Imhausen, published 2002, pages 420 - 428) For ancient observers to measure this period required some sort of clock. Such measurements were not reliable.
David M ‏, and Mathematics in the Ancient Near East Steele and Annette .‏ 428 (edited by John M -‏ 420 pages ‏, 2002 published ‏, Imhausen لكن الراصدين القدامى كانوا بحاجة الى ساعة من نوع ما لقياس الفترة الزمنية ،‏ ولم تكن مثل هذه القياسات جديرة بالثقة .‏