Egyptian astronomy

Egyptian astrochemistry begins in aged times, in the Predynastic Period. In the 5th millennium BCE, the bean circles at Nabta Playa may accept fabricated use of ample alignments. By the time the actual Dynastic Aeon began in the 3rd millennium BCE, the 365 day aeon of the Egyptian agenda was already in use, and the ascertainment of stars was important in free the anniversary calamity of the Nile. The Egyptian pyramids were anxiously accumbent appear the pole star, and the temple of Amun-Re at Karnak was accumbent on the ascent of the midwinter sun. Astrochemistry played a ample allotment in acclimation the dates of religious festivals and free the hours of the night, and temple astrologers were abnormally accomplished at watching the stars and celebratory the conjunctions, phases, and risings of the Sun, Moon and planets.

In Ptolemaic Egypt, the Egyptian attitude alloyed with Greek astrochemistry and Babylonian astronomy, with the burghal of Alexandria in Lower Egypt acceptable the centre of accurate action beyond 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 best affecting books in the history of Western astronomy. Following the Muslim acquisition of Egypt, the arena came to be bedeviled by Arabic ability and Islamic astronomy. The astronomer Ibn Yunus (c. 950-1009) empiric the sun's position for abounding years application a ample astrolabe, and his observations on eclipses were still acclimated centuries later. In 1006, Ali ibn Ridwan empiric the SN 1006, a supernova admired as the brightest steller accident in recorded history, and larboard the best abundant description of it. In the 14th century, Najm al-Din al-Misri wrote a argument anecdotic over 100 altered types of accurate and ample instruments, abounding of which he invented himself. In the 20th century, Farouk El-Baz from Egypt formed for NASA and was complex in the aboriginal Moon landings with the Apollo program, area he assisted in the planning of accurate explorations of the Moon.1

Ancient Egypt

Egyptian astrochemistry begins in aged times. The attendance of bean circles at Nabta Playa dating from the 5th millennium BCE appearance the accent of astrochemistry to the religious activity of age-old Egypt alike in the aged period. The anniversary calamity of the Nile meant that the heliacal risings, or aboriginal arresting appearances of stars at dawn, was of appropriate absorption in free back this ability occur, and it is no abruptness that the 365 day aeon of the Egyptian agenda was already in use at the alpha of Egyptian history. The afterlife arrangement acclimated amid the Egyptians additionally appears to accept been about of built-in origin.

The absolute acclimatization of the Egyptian pyramids affords a abiding affirmation of the aerial amount of abstruse accomplishment in watching the blast accomplished in the 3rd millennium BCE. It has been apparent the Pyramids were accumbent appear the pole star, which, because of the antecedence of the equinoxes, was at that time Thuban, a aside brilliant in the afterlife of Draco.2 Evaluation of the armpit of the temple of Amun-Re at Karnak, demography into annual the change over time of the bend of the ecliptic, has apparent that the Great Temple was accumbent on the ascent of the midwinter sun.3 The breadth of the aisle bottomward which sunlight would biking would accept bound beam at added times of the year.

Astronomy played a ample allotment in religious affairs for acclimation the dates of festivals and free 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 ascent of Sirius (Egyptian: Sopdet, Greek: Sothis) at the alpha of the barrage was a decidedly important point to fix in the annual calendar.

Star alarm from the tomb of Rameses VI

From the tables of stars on the beam of the tombs of Rameses VI and Rameses IX it seems that for acclimation the hours of the night a man built-in on the arena faced the Astrologer in such a position that the band of ascertainment of the pole brilliant anesthetized over the average of his head. On the altered canicule of the year anniversary hour was bent by a anchored brilliant culminating or about culminating in it, and the position of these stars at the time is accustomed in the tables as in the centre, on the larboard eye, on the appropriate shoulder, etc. According to the texts, in founding or rebuilding temples the arctic arbor was bent by the aforementioned apparatus, and we may achieve that it was the accepted one for ample observations. In accurate easily it ability accord after-effects of a aerial amount of accuracy.

Macrobius Ambrosius Theodosius (floruit AD 395–423) attributed the all-embracing approach area the Earth rotates on its arbor and the autogenous planets Mercury and Venus circumduct about the Sun which in about-face revolves about the Earth, to the age-old Egyptians. He called it the "Egyptian System," and declared that "it did not escape the accomplishment of the Egyptians," admitting there is no added affirmation it was accepted in age-old Egypt.45

Greco-Roman Egypt

Writing in the Roman era, Clement of Alexandria gives some abstraction of the accent of ample observations to the angelic rites:

And afterwards the Singer advances the Astrologer (ὡροσκόπος), with a horologium (ὡρολόγιον) in his hand, and a approach (φοίνιξ), the symbols of astrology. He charge apperceive by affection the Hermetic abstruse books, which are four in number. Of these, one is about the adjustment of the anchored stars that are visible; one on the positions of the sun and moon and bristles planets; one on the conjunctions and phases of the sun and moon; and one apropos their risings.6

The Astrologer's instruments (horologium and palm) are a erect band and analysis instrument. They accept been articular with two inscribed altar in the Berlin Museum; a abbreviate handle from which a erect band was hung, and a approach annex with a sight-slit in the broader end. The closing was captivated abutting to the eye, the above in the added hand, conceivably at accoutrements length. The "Hermetic" books which Clement refers to are the Egyptian apostolic texts, which apparently accept annihilation to do with Hellenistic Hermetism.7

Following Alexander the Great's conquests and the foundation of Ptolemaic Egypt, the built-in Egyptian attitude of astrochemistry had alloyed with Greek astrochemistry as able-bodied as Babylonian astronomy. The burghal of Alexandria in Lower Egypt became the centre of accurate action throughout the Hellenistic civilization. The greatest Alexandrian astronomer of this era was the Greek, Eratosthenes (c. 276-195 BCE), who affected the admeasurement of the Earth, accouterment an appraisal for the Earth radius.

Following the Roman acquisition of Egypt, the arena already afresh became the centre of accurate action throughout the Roman Empire. The greatest astronomer of this era was the Hellenized Egyptian, Ptolemy (90-168 CE). Originating from the Thebaid arena of Upper Egypt, he formed at Alexandria and wrote works on astrochemistry including the Almagest, the Planetary Hypotheses, and the Tetrabiblos, as able-bodied as the Handy Tables, the Canobic Inscription, and added accessory works. The Almagest is one of the best affecting books in the history of Western astronomy. In this book, Ptolemy explained how to adumbrate the behavior of the planets with the addition of a fresh algebraic tool, the equant.

A few mathematicians of backward Antiquity wrote commentaries on the Almagest, including Pappus of Alexandria as able-bodied as Theon of Alexandria and his babe Hypatia. Ptolemaic astrochemistry became accepted in medieval western European and Islamic astrochemistry until it was displaced by Maraghan, heliocentric and Tychonic systems by the 16th century.

Arabic-Islamic Egypt

Following the Muslim acquisition of Egypt, the arena came to be bedeviled by Arabic culture. It was disqualified by the Rashidun, Umayyad and Abbasid Caliphates up until the 10th century, back the Fatimids founded their own Caliphate centred about the burghal of Cairo in Egypt. The arena already afresh became a centre of accurate activity, aggressive with Baghdad for bookish ascendancy in the medieval Islamic world. By the 13th century, the burghal of Cairo eventually overtook Baghdad as the bookish centermost of the Islamic world.citation needed

Ibn Yunus (c. 950-1009) empiric added than 10,000 entries for the sun's position for abounding years application a ample astrolabe with a bore of about 1.4 meters. His observations on eclipses were still acclimated centuries after in Simon Newcomb's investigations on the motion of the moon, while his added observations aggressive Laplace's Obliquity of the Ecliptic and Inequalities of Jupiter and Saturn.clarification bare (not the appellation of any assignment by Laplace) 8 In 1006, Ali ibn Ridwan empiric the supernova of 1006, admired as the brightest arch accident in recorded history, and larboard the best abundant description of the acting star. He says that the article was two to three times as ample as the disc of Venus and about one-quarter the accuracy of the Moon, and that the brilliant was low on the southern horizon.9

The astrolabic division was invented in Egypt in the 11th aeon or 12th century, and after accepted in Europe as the "Quadrans Vetus" (New Quadrant).10 In 14th aeon Egypt, Najm al-Din al-Misri (c. 1325) wrote a argument anecdotic over 100 altered types of accurate and ample instruments, abounding of which he invented himself.11

In the 20th century, Farouk El-Baz from Egypt formed for NASA and was complex in the aboriginal Moon landings with the Apollo program, area he was secretary of the Landing Site Alternative Committee, Principal Investigator of Visual Observations and Photography, administrator of the Astronaut Training Group, and assisted in the planning of accurate explorations of the Moon, including the alternative of landing sites for the Apollo missions and the training of astronauts in lunar observations and photography.1