Editing History of astronomy (section)

===Egypt===
{{Main|Egyptian astronomy}}
[[File:Senenmut-Grab.JPG|thumb|Segment of the [[astronomical ceiling of Senenmut's Tomb]] (circa 1479–1458 BC), depicting constellations, protective deities, and twenty-four segmented wheels for the hours of the day and the months of the year]]

The precise orientation of the [[Egyptian pyramids]] affords a lasting demonstration of the high degree of technical skill in watching the heavens attained in the 3rd millennium BC. 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 (constellation)|Draco]].<ref>Ruggles, C.L.N. (2005), ''Ancient Astronomy'', pages 354–355. ABC-Clio. {{ISBN|1-85109-477-6}}.</ref> 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 [[winter solstice|midwinter]] Sun.<ref>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}}.</ref> The length of the corridor down which sunlight would travel would have limited illumination at other times of the year. The Egyptians also found the position of Sirius (the dog star), who they believed was Anubis, their jackal-headed god, moving through the heavens. Its position was critical to their civilisation as when it rose heliacal in the east before sunrise it foretold the flooding of the Nile. It is also the origin of the phrase "dog days of summer".<ref>{{Cite web |title=dog days {{!}} Etymology, origin and meaning of phrase dog days by etymonline |url=https://www.etymonline.com/word/dog%20days |access-date=2023-11-01 |website=www.etymonline.com}}</ref>

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 [[star]]s. The rising of [[Sirius]] ([[Egyptian language|Egyptian]]: Sopdet, [[Ancient Greek|Greek]]: Sothis) at the beginning of the inundation was a particularly important point to fix in the yearly calendar.

Writing in the [[Roman era]], [[Clement of Alexandria]] gives some idea of the importance of astronomical observations to the sacred rites:
<blockquote>And after the Singer advances the Astrologer (ὡροσκόπος), with a ''horologium'' (ὡρολόγιον) in his hand, and a ''palm'' (φοίνιξ), the symbols of [[ancient Egyptian astronomy|astrology]]. He must know by heart the [[Hermetism|Hermetic]] astrological books, which are four in number. Of these, one is about the arrangement of the fixed stars that are visible; one on the positions of the Sun and Moon and five planets; one on the conjunctions and phases of the Sun and Moon; and one concerns their risings.<ref>Clement of Alexandria, ''Stromata'', vi. 4</ref></blockquote>

The Astrologer's instruments (''horologium'' and ''palm'') are a [[plumb line]] and sighting instrument{{Clarify|date=November 2009}}<!--SEE TALK!-->. They have been identified with two inscribed objects in the [[Egyptian Museum of Berlin|Berlin Museum]]; a short handle from which a plumb line was hung, and a palm branch with a sight-slit in the broader end. The latter was held close to the eye, the former in the other hand, perhaps at arm's length. The "Hermetic" books which Clement refers to are the Egyptian theological texts, which probably have nothing to do with [[Hellenistic]] [[Hermetism]].<ref>Neugebauer O, ''Egyptian Planetary Texts'', Transactions, American Philosophical Society, Vol. 32, Part 2, 1942, Page 237.</ref>

From the tables of stars on the ceiling of the tombs of [[Rameses VI|Rameses&nbsp;VI]] and [[Rameses IX|Rameses&nbsp;IX]] it seems that for fixing the hours of the night a man seated on the ground faced the Astrologer in such a position that the line of observation of the [[pole star]] passed over the middle of his head. On the different days of the year each hour was determined by a fixed star [[culmination|culminating]] or nearly culminating in it, and the position of these stars at the time is given in the tables as in the centre, on the left eye, on the right shoulder, etc. According to the texts, in founding or rebuilding temples the [[north]] axis was determined by the same apparatus, and we may conclude that it was the usual one for astronomical observations. In careful hands it might give results of a high degree of accuracy.