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Egyptian astronomy begins in prehistoric times, in the Predynastic Period. In the 5th millennium BCE, the stone circles at Nabta Playa may have made use of astronomical alignments. By the time the historical Dynastic Period began in the 3rd millennium BCE, the 365 day period of the Egyptian calendar was already in use, and the observation of stars was important in determining the annual flooding of the Nile. The Egyptian pyramids were carefully aligned towards the pole star, and the temple of Amun-Re at Karnak was aligned on the rising of the midwinter sun. Astronomy played a considerable part in fixing the dates of religious festivals and determining the hours of the night, and temple astrologers were especially adept at watching the stars and observing the conjunctions, phases, and risings of the sun, moon and planets. In Ptolemaic Egypt, the Egyptian tradition merged with Greek astronomy and Babylonian astronomy, with the city of Alexandria in Lower Egypt becoming the centre of scientific activity across the Hellenistic world. Roman Egypt produced the greatest astronomer of the era, Ptolemy (90-168 CE). His works on astronomy, including the Almagest, became the most influential books in the history of Western astronomy. Following the Muslim conquest of Egypt, the region came to be dominated by Arabic culture and Islamic astronomy. The astronomer Ibn Yunus (c. 950-1009) observed the sun's position for many years using a large astrolabe, and his observations on eclipses were still used centuries later. In 1006, Ali ibn Ridwan observed the SN 1006, a supernova regarded as the brightest stellar event in recorded history, and left the most detailed description of it. In the 14th century, Najm al-Din al-Misri wrote a treatise describing over 100 different types of scientific and astronomical instruments, many of which he invented himself. In the 20th century, Farouk El-Baz from Egypt worked for NASA and was involved in the first Moon landings with the Apollo program, where he assisted in the planning of scientific explorations of the Moon.〔 == Ancient Egypt == Egyptian astronomy begins in prehistoric times. The presence of stone circles at Nabta Playa in Upper Egypt dating from the 5th millennium BCE show the importance of astronomy to the religious life of ancient Egypt even in the prehistoric period. The annual flooding of the Nile meant that the heliacal risings, or first visible appearances of stars at dawn, were of special interest in determining when this might occur, and it is no surprise that the 365 day period of the Egyptian calendar was already in use at the beginning of Egyptian history. The constellation system used among the Egyptians also appears to have been essentially of native origin. The precise orientation of the Egyptian pyramids serves as a lasting demonstration of the high degree of technical skill in watching the heavens attained in the 3rd millennium BCE. It has been shown the pyramids were aligned towards the pole star, which, because of the precession of the equinoxes, was at that time Thuban, a faint star in the constellation of Draco.〔Ruggles, C.L.N. (2005), ''Ancient Astronomy'', pages 354-355. ABC-Clio. ISBN 1-85109-477-6.〕 Evaluation of the site of the temple of Amun-Re at Karnak, taking into account the change over time of the obliquity of the ecliptic, has shown that the Great Temple was aligned on the rising of the midwinter sun.〔Krupp, E.C. (1988). "Light in the Temples", in C.L.N. Ruggles: Records in Stone: Papers in Memory of Alexander Thom. CUP, 473-499. ISBN 0-521-33381-4.〕 The length of the corridor down which sunlight would travel would have limited illumination at other times of the year. Astronomy played a considerable part in religious matters for fixing the dates of festivals and determining the hours of the night. The titles of several temple books are preserved recording the movements and phases of the sun, moon and stars. The rising of Sirius (Egyptian: Sopdet, Greek: Sothis) at the beginning of the inundation was a particularly important point to fix in the yearly calendar. One of the most important Egyptian astronomical texts was the Book of Nut, going back to the Middle Kingdom or earlier. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Egyptian astronomy」の詳細全文を読む スポンサード リンク
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