Decan

The decans (/ˈdɛkənz/; Egyptian bꜣktw or baktiu, "[those] connected with work"[1]) are 36 groups of stars (small constellations) used in the ancient Egyptian astronomy. They rose consecutively on the horizon throughout each earth rotation. The rising of each decan marked the beginning of a new decanal "hour" (Greek hōra) of the night for the ancient Egyptians, and they were used as a sidereal star clock beginning by at least the 9th or 10th Dynasty (c. 2100 BCE).

'Diagonal star table' from the late 11th Dynasty coffin lid; found at Asyut, Egypt. Roemer- und Pelizaeus-Museum Hildesheim

Because a new decan also appears heliacally every ten days (that is, every ten days, a new decanic star group reappears in the eastern sky at dawn right before the Sun rises, after a period of being obscured by the Sun's light), the ancient Greeks called them dekanoi (δεκανοί; pl. of δεκανός dekanos) or "tenths".

Decans continued to be used throughout the Renaissance in astrology and in magic, but modern astrologers almost entirely ignore them.

bꜣktw in hieroglyphs

Ancient Egyptian origins

Astronomical ceiling of Senemut Tomb showing various decans, as well as the personified representations of stars and constellations

Decans first appeared in the 10th Dynasty (2100 BCE) on coffin lids.[2] The sequence of these star patterns began with Sothis (Sirius), and each decan contained a set of stars and corresponding divinities. As measures of time, the rising and setting of decans marked 'hours' and groups of 10 days which comprised an Egyptian year. The ancient Book of Nut covers the subject of the decans.

There were 36[3] decans (36 × 10 = 360 days), plus five added days to compose the 365 days of a solar based year. Decans measure sidereal time and the solar year is six hours longer; the Sothic and solar years in the Egyptian calendar realign every 1460 years. Decans represented on coffins from later dynasties (such as King Seti I) compared with earlier decan images demonstrate the Sothic-solar shift.

According to Sarah Symons

Although we know the names of the decans, and in some cases can translate the names (Hry-ib wiA means 'in the centre of the boat') the locations of the decanal stars and their relationships to modern star names and constellations are not known. This is due to many factors, but key problems are the uncertainty surrounding the observation methods used to develop and populate the diagonal star tables, and the criteria used to select decans (brightness, position, relationship with other stars, and so on).[4]

Later developments

These predictable heliacal re-appearances by the decans were eventually used by the Egyptians to mark the divisions of their annual solar calendar. Thus the heliacal rising of Sirius marked the annual flooding of the Nile.

Eventually this system led to a system of 12 daytime hours and 12 nighttime hours, varying in length according to the season. Later, a system of 24 "equinoctial" hours was used.[5]

After astrology was introduced to Egypt, various systems attributing astrological significance to decans arose. Decans were connected, for example, with various diseases and with the timing for the engraving of talismans for curing them;[6] with decanic "faces" (or "phases"), a system where three decans are assigned to each zodiacal sign, each covering 10° of the zodiac, and each ruled by a planetary ruler (see below); and correlated with astrological signs.[7]

Descriptions of the decans

Decans are named in various Greco-Egyptian sources, many Hermetic writings, the Testament of Solomon,[8] and the writings of Aristobulus of Paneas.[9] Julius Firmicus Maternus, Cosmas of Maiuma, Joseph Justus Scaliger, and Athanasius Kircher.[8]

Images of the decans are described in Hermetic writings, by the Indian astrologer Varāhamihira, in the Picatrix, and in Japanese writings.[10] Varāhamihira's images of the decans was influenced by Greco-Egyptian, if not Hermetic, depictions of the decans by way of the Yavanajataka.[11] Their role in Japanese astrology may have derived from an earlier Chinese[12] or Indian form[13] possibly from adding the twelve animals of the Chinese zodiac to a list of twenty-four hour stars.[12] They were most common between the Kamakura and Edo periods.[13]

The first original Decan position due to the precession in ancient times started at 0° of Cancer when the heliacal rising of Sirius (Egyptian Sepdet; Greco-Egyptian: Sothis) on sunset like Jewish and Islamic calendars marking the Egyptian New Year and now the 1st decan falls on 0° of Leo at July 20 in the Julian calendar, that is July 22/23 on the Gregorian calendar.

Names of the Decans

Western Zodiac	Decan	Original Decan Position due to the Precession in Ancient Times	Ancient Egyptian Transliteration [Ptolemaic Variant Transliteration][14]	Greco-Egyptian[8]	Testament of Solomon[8][15][16]	Aristobulus's names[9]	Greek Hermeticism[8][17][18]	Latin Hermeticism[8][18][19]	Firmicus[8]	Cosmas[8][20]	Scalinger[8]	Kircher[8]
Aries	1	28		Χont-har	Rhyax or Ruax	Bendonc	Chenlachori	Aulathamas	Senator or Asiccan	Aidoneus	Asiccan	Arueris
	2	29	Sasaqed [Siket]	Si-ket	Barsafael	Mensour	Chontaret	Sabaoth	Senacher or Asenter	Persephone	Senacher	Anubis
	3	30		Xont-χre	Artosael or Arôtosael	Carexon	Siket	Disornafais	Sentacher or Asentacer	Eros	Acentacer	Horus
Taurus	4	31	Khau [Erō, Aro'ou]	Xau	Horopel	Gisan	Soou	Jaus	Suo or Asicat	Charis	Asicath	Serapis
	5	32	Ārt [Khōo'ou]	Arat	Kairoxanondalon or Iudal	Tourtour	Aron	Sarnotois	Aryo or Ason	die Horen	Viroaso	Helitomenos
	6	33	Remen-Ḥeru-An-Saḥ [Remena'are]	Remen-hare	Sphendonael	Ballat	Rhomenos	Erchmubris	Romanae or Arfa	Litai	Aharph	Apophis
Gemini	7	34	Mesdjer-Saḥ [Thosalk]	Θosalk	Sphandor	Farsan	Xocha	Manuchos	Thesogar or Tensogar	Thetys	Thesogar	Tautus
	8	35	Remen-Kher-Saḥ [O'ouare]	Uaret	Belbel	Vaspan	Ouari	Samurois	Ver or Asuae	Kybele	Verasua	Cyclops
	9	36	A-Saḥ [T'pēsōthis]	Phu-hor	Kourtael or Kurtaêl	Parquia	Pepisoth	Azuel	Tepis or Atosoae	Praxidike	Tepisatosoa	Titan
Cancer	10	1 (= 0' Cancer)	Sepdet [Sōthis]	Sopdet	Metathiax	Panem	Sotheir	Seneptois	Sothis or Socius	Nike	Sothis	Apollun
	11	2	Depā-Kenmut [Sit]	Seta	Katanikotael	Catarno	Ouphisit	Somachalmais	Sith	Herakles	Syth	Hecate
	12	3	Kenmut [Khno'oumis]	Knum	Saphthorael or Saphathoraél	Hellors	Chnouphos	Charmine	Thiumis or Thumus	Hekate	Thuimis	Mercophta
Leo	13	4	Kher-Khept-Kenmut [Kharkhno'oumis]	Χar-Knum	Phobothel or Bobêl	Jarea	Chnoumos	Zaloias	Craumonis or Afruicois	Hephaistos	Aphruimis	Typhon
	14	5	Ḥā-Djat [Ētēt]	Ha-tet	Leroel or Kumeatêl	Effraa	Ipi	Zachor	Sic	Isis	Sithacer	Peroeus
	15	6	Peḥui-Djat [Pho'outēt]	Phu-Tet	Soubetti	Hayas	Phatiti	Frich	Futile or Eisie	Sarapis	Phuonisie	Nepenthe
Virgo	16	7	Tjemat-Ḥert [Tōm]	Tom	Katrax or Atrax	Angaf	Athoum	Zamendres	Thumis or Thinnis	Themis	Thumi	Isis
	17	8	Tjemat-Khert (O'oueste-Bikōti)	Uste-bikot	Jeropa or Ieropaêl	Bethapen	Brysous	Magois	Tophicus or Tropicus	Moirai	Thopitus	Pi-Osiris
	18	9	Ustji [Aphoso]	Aposot	Modobel or Buldumêch	Baroche	Amphatham	Michulais	Afut or Asuth	Hestia	Aphut	Cronus
Libra	19	10	Bekatji [So'oukhōs]	Sob‿χos	Madero or Naôth	Zercuris	Sphoukou	Psineus	Seuichut or Senichut	Erinys	Serucuth	Zeuda
	20	11	Depā-Khentet [T'pēkhonti]	Tpa-χont	Nathotho or Marderô	Baham	Nephthimes	Chusthisis	Sepisent or Atebenus	Kairos	Aterechinis	Omphta
	21	12		Xont-har	Alath	Pieret	Phou	Psamiatois	Senta or Atepiten	Loimos	Arpien	Ophionius
Scorpio	22	13	Sapt-Khennu [S'ptkhne]	Spt-χne	Audameoth	Haziza	Name	Necbeuos	Sentacer or Asente	Nymphs	Sentacer	Arimanius
	23	14		Sesme	Nefthada	Nacy	Oustichos	Turmantis	Tepsisen or Asentatir	Leto	Tepiseuth	Merota
	24	15		Si-sesme	Akton	Alleinac	Aphebis	Psermes	Sentineu or Aterceni(-cem)	Kairos (repeated)	Senicer	Panotragus
Sagittarius	25	16	Ḥer-Ab-Uia ['Erēo'ouō]	Hre-ua	Anatreth	Ortusa	Sebos	Clinothois	Eregbuo or Ergbuo	Loimos (repeated)	Eregbuo	Tolmophta
	26	17		Sesme	Enautha or Enenuth	Daha	Teuchmos	Thursois	Sagon	Kore	Sagen	Tomras
	27	18	Kenmu [Konime]	Konime	Axesbyth or Phêth	Satan	Chthisar	Renethis	Chenene or Chenem	Ananke	Chenen	Teraph
Capricorn	28	19	Semdet [Smat]	Smat	Hapax or Harpax	Eracto	Tair	Renpsois	Themeso	Asklepios	Themeso	Soda
	29	20	Sert [Srō]	Srat	Anoster	Salac	Epitek	Manethois	Epiemu or Epimen	Hygieia	Epima	Riruphta
	30	21	Sasa-Sert [Sisrō]	Si-srat	Physikoreth or Alleborith	Seros	Epichnaus	Marcois	Omot	Tolma	Homoth	Monuphta
Aquarius	31	22	Khukhu [T'pēkhou]	Tpa-χu	Aleureth or Hephesimireth	Tonghel	Isi	Ularis	Oro or Asoer	Dike	Oroasoer	Brondeus
	32	23	Baba [Khou(?)]	Xu	Ichthion	Anafa	Sosomo	Luxois	Cratero or Astiro	Phobos	Astiro	Vucula
	33	24		Tpa-Biu	Achoneoth or Agchoniôn	Simos	Chonoumous	Crauxes	Tepis or Amasiero	Osiris	Tepisatras	Proteus
Pisces	34	25		Biu	Autoth or Autothith	Achaf	Tetimo	Fambais	Acha or Atapiac	Okeanos	Archatapias	Rephan
	35	26		Xont-Har	Phtheneoth or Phthenoth	Larvata	Sopphi	Flugmois	Tepibui or Tepabiu	Dolos	Thopibui	Sourut
	36	27		Tpi-biu	Bianakith	Ajaras	Syro	Piatris	Uiu or Aatexbui	Elpis	Atembui	Phallophorus

East Asian Zodiac

The East Asian zodiac features Decans in the form of Thirty-six Calendar Animals (Sanjūroku Kingyōzō 三十六禽形像; alternatively known as the Chikusan Reiki 畜産暦). The group originated in China, wherein the 36 were divided into four clusters, with each cluster made up of nine animal-deity pairs (4 × 9 = 36). The four clusters represent the four cardinal directions (north, south, east, west). The animals are also grouped in triads—three animals are combined under one of 12 Zodiac Signs (3 × 12 = 36). In Japan, the group appeared in the Nichū Reki 二中暦, a Japanese calendar from the second half of the 14th century. Curiously, eight of the 36 appear “fox like”—almost identical in physical attributes. These eight (presented below) include the tanuki, mujna, fox, wolf, jackal, wild cat, and wild male-female dogs. The mujina, fox and rabbit are combined under the zodiacal sign of the rabbit. The tanuki, leopard, and tiger are combined under the zodiacal sign of the tiger. Western scholars have mistranslated tanuki and mujina for decades as “badger” or “racoon-dog.” But in extant artwork like that shown below, the beasts are clearly “fox-like.” It is therefore puzzling why Western scholars call them badgers and racoon dogs.:[21][22]

East Asian Zodiac[22]

Zodiac	First animal	Second animal	Third animal
Rat	Cat (貓)[note 1]	Rat (鼠)	Bat (伏翼)
Ox	Cattle (牛)	Crab (蟹)	Turtle (鱉)
Tiger	Raccoon dog (狸)[note 2]	Leopard (豹)	Tiger (虎)
Rabbit	Fox (狐)[note 3]	Rabbit (兔)	Badger (貉)[note 4]
Dragon	Dragon (龍)	Shark (鮫)	Fish (魚)
Snake	Cicada (蟬)	Carp (鯉)	Snake (蛇)
Horse	Deer (鹿)	Horse (馬)	Roebuck (麞)
Goat	Sheep (羊)	Goose (雁)	Hawk or falcon (鷹)
Monkey	Gibbon (狖)[note 5][23][24]	Ape (猿)[note 6][24]	Monkey (猴)[note 7][24]
Rooster	Raven (烏)	Chicken (雞)	Pheasant (雉)
Dog	Dog (狗, see Inugami)	Wolf (狼)	Ch. Dhole, Ja. Honshu wolf (豺)
Pig	Pig (豕)[note 8][21]	Domestic pig (豕 俞)[note 9][21]	Wild boar (豬)[note 10][21]

Table of faces (or decanates)

There were two main versions of rulership given to the decans in the ancient world: Chaldean rulership and rulership by Triplicity.

"The Faces of the Planets" * (Lilly)[25]

Sign	First Decan ruler (0 - 9.999 deg.)	Second Decan ruler (10 - 19.999 deg.)	Third Decan ruler (20 - 29.999 deg.)
Aries	Mars	Sun	Venus
Taurus	Mercury	Moon	Saturn
Gemini	Jupiter	Mars	Sun
Cancer	Venus	Mercury	Moon
Leo	Saturn	Jupiter	Mars
Virgo	Sun	Venus	Mercury
Libra	Moon	Saturn	Jupiter
Scorpio	Mars	Sun	Venus
Sagittarius	Mercury	Moon	Saturn
Capricorn	Jupiter	Mars	Sun
Aquarius	Venus	Mercury	Moon
Pisces	Saturn	Jupiter	Mars

* as used as an essential dignity in astrology.

Notice that rulerships follow a repeating pattern, the so-called "Chaldean" order of the planets: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon. This planetary order, in which the Sun stands at the center of the continuum, with the planets between the Sun and the Earth on one side and the outer planets on the other side, reflected the perception of the speed of each planet's motion as seen from the Earth.

"The Faces of the Planets" * (Triplicity)

Sign	First Decan ruler (0 - 9.999 deg.)	Second Decan ruler (10 - 19.999 deg.)	Third Decan ruler (20 - 29.999 deg.)
Aries	Mars	Sun	Jupiter
Taurus	Venus	Mercury	Saturn
Gemini	Mercury	Venus	Saturn
Cancer	Moon	Mars	Jupiter
Leo	Sun	Jupiter	Mars
Virgo	Mercury	Saturn	Venus
Libra	Venus	Saturn	Mercury
Scorpio	Mars	Jupiter	Moon
Sagittarius	Jupiter	Mars	Sun
Capricorn	Saturn	Venus	Mercury
Aquarius	Saturn	Mercury	Venus
Pisces	Jupiter	Moon	Mars

Decans or "faces" are the least important of the essential dignities, representing about one-fifteenth of a planet's overall strength in medieval astrology.

Ancient India

In India, the division of the zodiac into 36 ten degree portions is called either the drekkana (drekkāṇa),the dreshkana (dreṣkāṇa), or the drikana (dṛkāṇa).[26]

The iconography and use of the drekkana's is mention earliest by Sphujidhvaja in Yavanajataka (269-70 CE), and given detailed treatment by Varahamihira in his Brihat-Samhita (550 CE). Modern scholars believe the decans were imported into India through the Greeks, who learned about them from the Egyptians.[27]

There are multiple types of drekkana in use in Indian astrology. The parivritti drekkana goes in order of the signs; the first decan is Aries, the second is Taurus, the third is Gemini, the fourth is Cancer, etc. Then there is the trinal calculation which utilizes the elemental trines to each sign; In Aries there is Aries, Leo, and Sagittarius, while in Taurus there is Taurus, Virgo, and Capricorn. There are in total four variations of drekkana calculations. Indian astrologers will calculate these signs (varga) and create a new chart based upon the sign placement for predictive purposes.

See also

• Asterism (astronomy)
• Astronomical ceiling of Senemut Tomb
• Decan (astrology)
• Drekkana
• Line of advantage
• Nakshatra
• Palazzo Schifanoia, Ferrara

Footnotes

1. See Bakeneko
2. See Bake-danuki
3. See Huli Jing and Kitsune
4. See Mujina
5. See "You"
6. See "Yuan"
7. See "Hou"
8. Gundel swaps this with the next entry
9. Gundel lists this as "Tier Yu" or "Yu animal," describing it as a wolf-like
10. Gundel gives Swallow

References

1. Keyser, Paul; Scarborough, With John (26 June 2018). The Oxford Handbook of Science and Medicine in the Classical World. ISBN 9780190878832.
2. Symons, S. L., Cockcroft, R., Bettencourt, J. and Koykka, C. (2013). Ancient Egyptian Astronomy [Online database] Diagonal Star Tables
3. von Bomhard, Dr. A. S., The Egyptian Calendar: A Work for Eternity, London, 1999, page 51
4. Symons, S. L. "A Star's Year: The Annual Cycle in the Ancient Egyptian Sky". Archived 2013-06-15 at the Wayback Machine. In: Steele, J. M. (ed.), Calendars and Years: Astronomy and Time in the Ancient World. Oxbow Books, Oxford, pp. 1–33.
5. Neugebauer, Otto (1983) [1955]. "The Egyptian "Decans"". Astronomy and History: Selected Essays. New York: Springer. pp. 205–209. doi:10.1007/978-1-4612-5559-8. ISBN 978-0-387-90844-1. Neugebauer, Otto (1969) [1957]. The Exact Sciences in Antiquity (2 ed.). Dover Publications. pp. 81–88. ISBN 978-0-486-22332-2.
6. see for example, RUELLE, C. E., Hermès Trismégiste, Le livre sacré sur les décans. Texte, variantes et traduction française, Revue de philologie, de littérature et d'histoire anciennes, n.s.:32:4 (1908:oct.) p .247
7. Julius Firmicus Maternus, Matheseos IV/22.
8. Dekane und Dekansterbilder by Wilhelm Gundel, pub. J.J. Augustin, Glückstadt und Hamburg, 1936, p.77-81
9. Gundel, p. 406-408
10. Gundel, p.223-225
11. "The Indian Iconography of the Decans and Horâs" by David Pingree, Journal of the Warburg and Courtauld Institutes, vol. 26, no. 3/4 (1963), p. 223-254
12. Gundel, p. 217-221
13. "Bukkyō tenbugaku-senseijutsu no zuzō gakuteki junmen: sanjū rokkin to Dekan" by Yano Michio, Dōshisha daigaku rikō kenkyū hōkoku, 48, no 4 (2008), 1-6.
14. Budge, E. A. Wallis (Ernest Alfred Wallis) (1904-01-01). The gods of the Egyptians; or, Studies in Egyptian mythology. Chicago : Open Court Publishing Co.
15. Gundel, p.49-62
16. The Testament of Solomon, translated by Frederick Cornwallis Conybeare, Jewish Quarterly Review, October, 1898. Ed. Joseph Peterson, 1997, Esoteric Archives
17. "Hermès Trismégiste: Le Livré Sacre sur les Décans: Texte, variantes et traduction française" by C.E. Ruelle, Revue de Philologie October 1908, p.247-277
18. Gundel, p.374-383
19. "Hermes Trismegistus: Liber Hermetis, Book I" trans. Robert Zoller, ed. Robert Hand, p.iii-12
20. Gundel, p.353-354
21. Gundel, p. 216-221, 225
22. "三十六禽" [Thirty-Six Animals]. Buddhist Dictionary. Buddhistdoor International. Archived from the original on 2015-02-18. Retrieved 2021-01-24.
23. The gibbon in China: an essay in Chinese animal lore by Robert van Gulik, Brill Publishers, 1967, p.31
24. Bencao Gangmu: Compendium of Materia Medica, tr. Luo Xiwen, Foreign Languages Press, 2003, p.4124
25. William Lilly, Christian Astrology (London, 1647), pp. 104, 105.
26. Monier Williams Sanskrit Dictionary
27. Pingree, David (1963). "The Indian Iconography of the Decans and Horas". Journal of the Warburg and Courtauld Institutes. 26 (3/4): 223–254. doi:10.2307/750493. JSTOR 750493.

Further reading

• Symons, Sarah (2014). "Egyptian "Star Clocks"". In Ruggles, Clive L.N. (ed.). Handbook of Archaeoastronomy and Ethnoastronomy. New York: Springer. pp. 1495–1500. ISBN 978-1-4614-6140-1.
• van der Waerden, B. L. (January 1949). "Babylonian Astronomy. II. The Thirty-Six Stars". Journal of Near Eastern Studies. 8 (1): 6–26. doi:10.1086/370901. JSTOR 542436. S2CID 222443741. The property of the Chaldean Decans that one of them rose every ten days made them fit to be assimilated to the Egyptian decans. This assimilation was performed in the decan lists of Hellenistic astrology.

External links

• Symons, S.L., Cockcroft, R., Bettencourt, J. and Koykka, C., 2013. Ancient Egyptian Astronomy. [Online database] Available at: <http://aea.physics.mcmaster.ca/>.
• Egypt Astronomy/Astrology: The decans
• Decan meanings, from Paul Christian's The History and Practice of Magic.