If you observe the sun rising in the east and setting in the west over the course of a year, it would appear to follow along a certain band of the sky. This is called the ecliptic, which is defined as the “great circle representing the apparent annual path of the sun.” The illustration here should prove helpful. The moon likewise follows along this band of sky. Every night it will appear in a different section of it before returning to its original place, a cycle which takes around 28 days. These different sections can be called lunar stations in that the moon temporarily "resides" in each one before migrating to the next. The circle or band of sky can thus be divided into 27 or 28 parts. One could also divide it into 12 parts (the zodiac), which was the practice of the Babylonians by the year 500 BCE. This was taken up by the Greeks and by the second century BCE what we would recognize as western astrology emerged with the horoscope, which was based on the zodiac. The ancient Indian model of astrology, which was likewise influenced by Babylonian sources, initially based itself however on the lunar stations.
In ancient India the lunar stations were and still are called nakṣatra. In early Vedic times nakṣatra originally just meant star and later came to refer to constellations constituting lunar stations along the ecliptic. A complete list of 28 nakṣatra-s is first provided in the Atharva Veda. This was probably an indigenous development as there is no evidence the Indians received this model from Babylon. However, the Chinese by the fifth century BCE had developed their own model of 28 lunar stations (the xiu 宿), which led many in the last century to suspect both must have a common origin, though there is no substantial evidence to prove this. In 1919, the Assyriologist Carl Bezold thought he discerned Babylonian influence in Chinese texts, a thesis which was accepted by figures like Joseph Needham and Edward Schafer. David Pankenier, however, has recently (2014) has refuted this (see here).
02. 畢宿 Rohiṇī
04. 參宿 Ārdrā
05. 井宿 Punarvasū
07. 柳宿 Aślesā
09. 張宿 Pūrvaphālgunī
10. 翼宿 Uttaraphālgunī
11. 軫宿 Hasta
13. 亢宿 Svāti
15. 房宿 Anurādhā
16. 心宿 Jyeṣṭha
17. 尾宿 Mūla
23. 危宿 Śatabhiṣaj
24. 室宿 Pūrvabhādrapadā
25. 壁宿 Uttarabhādrapadā
26. 奎宿 Revatī
28. 胃宿 Bharaṇī
Generally in the 27 model each nakṣatra can occupy equal space, whereas in the 28 model the distances vary, and are measured by muhūrta (the time it takes the moon to pass through its space). A muhūrta is like an hour in that there are 30 per day, each comprised of 48 minutes (1440 minutes ÷ 48 = 30). Alternatively, Abhijit can be recognized yet subsumed under Uttarāṣāḍhā or Śravaṇa, as in the Mātaṅgī-sūtra 摩登伽經 (T 1300).
The number 27 divides into whole numbers such as with the ecliptic being divided into 108 pāda-s or quarters (.25), where each nakṣatra can be evenly assigned 4 pāda-s (108 ÷ 27 = 4). The twelve zodiacs, which were originally introduced to India from Babylonian and Hellenistic sources, are each assigned 9 pāda-s of the ecliptic (108 ÷ 12 = 9). The 9 pāda-s of a zodiac are divided among 3 nakṣatra-s which they are associated with. For example, Leo has the following assignments according to the Xiuyao jing 宿曜經 (T 1299), translated into Chinese (or rather compiled) in the mid-eighth century:
On the Indian calendar the name of each day is derived from the nakṣatra in which the moon is in that night. The model Amoghavajra used does not use numerals to specify days and it is quite clear about this difference with the Chinese calendar. Some will predictably be visibly ahead or behind it, which is likened to a calf and its mother. This highlights that the model is arithmetic rather than observational.
A month is named based on which nakṣatra the moon is in on the night of the fifteenth day of the śukla-pakṣa (waxing moon), which is the nominal full moon (the pūrṇāmānta method), though the actual full moon can visibly vary by a day, in contrast to the Chinese calendar where a month commences from the new moon (the amānta method). See here for the calendar table.
The aforementioned Mātaṅgī-sūtra in Chinese translation is exceptional in using the latter new moon method in contrast to the original Sanskrit version, but the gnomonic measurements of the Chinese translation also reflect revisions suited to a position north of India in Central Asian and moreover the text displays occidental influences. In Amoghavajra's Xiuyao jing the first month is Caitra (角), corresponding to the second Chinese lunar month, though Vaiśākha can also be reckoned as the beginning of the year.
As a component to lunar astrology, each nakṣatra is associated with an Indian deity. This is a very ancient Indian custom. They are further associated with gotra names and foods, though these vary considerably in the texts. A person is also associated with the nakṣatra they are born under to which predictions about their personal character and fate are made. Auspicious activities are also prescribed for each day. This is easily determined if you know what day on the East Asian lunar calendar you were born on.
The following lists the Chinese xiu, Sanskrit nakṣatra, (Sanskrit month name), and associated deity plus variant in the Xiuyao jing if applicable. The associated deities are originally listed in the Nakṣatrakalpa of the Atharvavedapariśiṣṭā. It is unclear the reason behind the variant deities.
04. 參宿 Ārdrā – Rudra.
05. 井宿 Punarvasū – Aditi.
09. 張宿 Pūrvaphālgunī – Bhaga (Vasu).
10. 翼宿 Uttaraphālgunī (Phālguna) – Aryaman.
11. 軫宿 Hasta – Āditya (Savitṛ)
13. 亢宿 Svāti – Vāyu.
15. 房宿 Anurādhā – Mitra.
16. 心宿 Jyeṣṭha (Jyaiṣṭha) – Indra.
17. 尾宿 Mūla – Nirṛti.
23. 危宿 Śatabhiṣaj – Varuṇa.
24. 室宿 Pūrvabhādrapadā (Bhādraphada) – Ajapāda.
25. 壁宿 Uttarabhādrapadā – Ahirbudhnya.
26. 奎宿 Revatī – Pūṣan.
28. 胃宿 Bharaṇī – Yama.
The nakṣatra-s themselves are also regarded as deities in various esoteric Buddhist works. The respective deities are also represented in art. One fine example is the “Deities of the Five Planets and Twenty-Eight Constellations” 五星二十八宿神形圖 (Osaka City Museum of Fine Arts), which is attributed either to Zhang Sengyao張僧繇 (c. 490-540) or Liang Lingzan 梁令瓚 (a contemporary of Yixing 一行 683–727). See here for the full image file.
The iconography as line drawings is also cataloged in the Japanese Butsuzō zui 佛像圖彙 (see here for the text) from 1789.
The seven planets (Skt. sapta-grahāḥ) also naturally feature prominently in Buddhist astrology. These seven include the sun, moon and five visible planets. Uranus, Neptune and Pluto were unknown in the ancient world. In English “planet” used to include the sun and moon until the 1630s. Likewise in the sun and moon in Sanskrit can be considered graha-s. Here graha is defined as “seizing, laying hold of”. It seems there are multiple explanations for why graha would mean planet. Spirits and demons are understood as seizing and exerting influences on people, as so too it was believed the planets were capable.
In India an additional two “hidden planets” are added: Rāhu and Ketu, which then comprise nine planets.
Rāhu in Indian mythology is the demon said to be responsible for devouring planets and causing eclipses. The concept underwent development over time. He is first explicitly named in the Atharva Veda, and later in the Mahābhārata and Purāṇas associated with Svarbhānu who appears in the earlier Rg Veda. He was first described as a disembodied demonic head consuming the sun and moon, but later as a result of Greek influences in the early Gupta period he was revised as being the ascending node of the moon in astronomical literature, envisioned as a dark or hidden planet from which calculations could be made for predicting eclipses, and indeed it worked.
Later this was coordinated with the entity Ketu, which became the descending node of the moon. The original Vedic meaning of ketu, however, meant rays of light and this came to refer to comets, the earliest reference of which is found in the Atharva Veda. Ketu was initially conceived of as solely the personification of comets, but sometime around or after 800 CE it was understood at the descending node of the moon. By the early second millennium Rāhu's imagery was further revised and he became a head of a serpent with Ketu as its tail owing perhaps to the influences from Middle Eastern astrology.
While Chinese texts have standard names for the seven planets, Chinese Buddhist works and almanacs will sometimes use transliterated loanwords from other languages. Amoghavajra provides in the Xiuyao jing the names of the seven planets in Chinese, Sogdian, Persian and Sanskrit. Their various names are as follows. The Persian terms are numerals, not planet names, used to indicate the day of the week.
Sogdian: 密, 蜜 (myr).
Persian: 曜 (ēw).
Sanskrit: 阿彌底耶, 阿儞底耶 (āditya).
Chinese: 月, 太陰.
Sogdian: 漠, 莫 (m'x).
Sanskrit: 蘇摩 (soma).
Chinese: 火星, 熒惑.
Sogdian: 雲漠, 雲漢 (wnx'n).
Persian: 勢 (sĕ).
Sanskrit: 盎哦囉迦 (aṅgāraka).
Chinese: 水星, 辰星.
Sogdian: 咥 (ṭyr).
Persian: 掣, 製 (čahār).
Sanskrit: 部陀 (budha).
Chinese: 木星, 歳星.
Persian: 本 (panǰ).
Sanskrit: 勿哩訶娑跛底 (bṛhaspati).
Chinese: 金星, 太白, 啟明, 長庚.
Sogdian: 那歇, 那頡 (n'xyẟ).
Persian: 數 (šaš).
Persian: 翕, 欲 (haft).
Sanskrit: 賖乃以室折羅, 拾室悉羅 (śanaiścara).
Planets associated with weekdays was a custom Buddhists adopted in India perhaps around the fourth of fifth century, which became it seems widespread among all Indians. The standard ordering of the seven-day week as we know it today originated in Egypt around the Common Era. The seven-day week was probably first employed around the Eastern territories of the Roman empire, the first usage found in the work of Dio Cassius (born 155 CE). It later became widespread from the third century before being adopted by Constantine in 321. Around the third to fourth centuries it was introduced into India. In the Vṛddhayavanajātaka, an astrological work by Mīnarāja dated to 300-325, the planets are for the first time in India listed in the temporal order of their regency over the days of the week. The earliest extant inscription referring to the seven-day week is dated to June 21st, 484 or 165 of the Gupta era during the reign of Budhagupta (r. c. 477-500).
This ordering of weekdays is a union of the Egyptian belief in deities overseeing each of the twenty-four hours and the Greek cosmological concept of concentric spheres. The spheres run in the descending order of Saturn, Jupiter, Mars, the Sun, Venus, Mercury and the Moon. The first hour of the first day is assigned to Saturn, the second hour to Jupiter, the third to Mars, and so on. The twenty-fifth hour (the first hour of the second day) is assigned to the Sun. The forty-ninth hour is assigned to the Moon. There are also earlier variant orderings which are reflected in Chinese translations.
As days of the week, each planet has astrological significance. Auspicious and inauspicious activities are assigned to each day. The fate of an individual is also influenced by which day they are born on. Furthermore, predictions about the future are made if certain weekdays fall on specific days of the lunar calendar.
In Hellenistic astrology, which deeply influenced Indian astrology and to some extent Chinese Buddhist models of astrology, the planets on the horoscopic chart are extremely significant. Jupiter, the Moon and Venus are positive or benefic, whereas Saturn and Mars are negative or malefic. The Sun and Mercury are of mixed qualities. These influences can be altered by various factors, such as which zodiacal house they are located in. The geometric relationships between the planets on a chart (called 'aspect') also influence events and individual fates. These concepts differ from native Chinese ones (Saturn for example is regarded as auspicious). These occidental ideas influenced late Tang literati society and actually displaced, at least for a time in the ninth century, the Chinese model in popular literature. However, at least one eminent court specialist in calendars in the following Song dynasty in the tenth century was also an expert in Hellenistic astrology.
Native Chinese astrology includes an art transliterated literally as “field allocation” 分野, which is a set of astral-terrestrial correspondences which assigns segments of the sky to geographical areas of China (designated by their ancient country names) and interprets the passage of planets through varying zones as being portentous, in particular conjunctions. This model can be traced back to the age of Confucius, long before any known Sino-Indian relations. Unlike in Hellenistic and Indian astrology, the concern is the state and not individuals. In the Warring States (403–221 BCE) period it was entirely sino-centric, but by the Han came to incorporate non-Chinese geographical zones as well as concepts such the five elements 五行 and yin-yang 陰陽 theory. By the late Tang (ninth century), the occidental and Chinese systems had been partially integrated.
In Mantrayāna Buddhist practice, there are mantras for each planet or all of them collectively, used either to enhance their positive influences or deflect their negative influences. These practices can be coordinated according to when it is astrologically appropriate to do so. In the Taishō canon the relevant texts are found between T 1302 ~ T 1312. The main mantras therein tentatively deciphered are as follows:
The Sun's mantra:
namaḥ ratna-trayāya namaḥ sūrya sarva-nakṣatra-rājāya oṃ amoghasya śāte svāhā
The Moon's mantra:
oṃ candra nakṣatra-rājāya śāte svāhā
oṃ aṅgāraka arogya svāhā
oṃ budha nakṣatra svamina induja svāhā
oṃ bṛhaspati nama pitṛvanāya mali vardhani svāhā
oṃ śukra adhvan vrā rājāya śrī kavi svāhā
oṃ śanaiścara nakṣatra prahā manā rupaya puṣṭikari svāhā
oṃ rāhuna asura-rājāya suma śatunaya śāntikari svāhā
oṃ vajra ketunā nakṣatra-rājāya hūṃ svāhā
There is a separate set of mantras appended to the Tejaprabha dhāraṇī (T 964), though these appear to have not been part of the original text:
namaḥ samantabuddhanāṃ oṃ mahāśubhiya svāhā
namaḥ samantabuddhanāṃ oṃ indrāya svāhā
namaḥ samantabuddhanāṃ oṃ varuṇāya svāhā
namaḥ samantabuddhanāṃ oṃ agniye svāhā
namaḥ samantabuddhanāṃ oṃ pṛthiviye svāhā
namaḥ samantabuddhanāṃ oṃ rāhula asurarājaya svāhā
namaḥ samantabuddhanāṃ oṃ praketunkṣatrarajāya hūṃ svāhā
namaḥ samantabuddhanāṃ oṃ aditya svāhā
namaḥ samantabuddhanāṃ oṃ saumaya svāhā
The planets each possesses unique features in iconography where they are depicted in human forms. The earliest extant representations of the planetary deities in India are from the fifth century (Gupta period). Chinese artists generally depicted the deities in Chinese garb with associated animal caps. One noteworthy extant specimen is "Tejaprabhā Buddha and the Five Planets" 熾盛光佛并五星圖 from Qianning 乾寧 4 (897 CE) by Zhang Huaixing 張淮興 from Dunhuang (British Museum Asia OA 1919,1-1,0.31).
A Brahmin depicting Saturn, carrying a staff and directing the ox. Atop him is an ox head.
The female figure on the bottom is Venus depicted as a beautiful lady playing the pipa 琵琶. Her skin tone is snow white, reflecting a Tang aesthetic. She has a bird hat atop her head.
At the bottom right the four-armed heterodox figure is Mars. He has a donkey atop his head. He carries an arrow, bow, double-edged sword and trident.
To the top there is another female figure dressed in Chinese attire holding a brush and paper with a monkey atop her head. She is Mercury.
The minister in the top left is Jupiter. He carries a plate of flowers and fruits while wearing a pig hat.
The aforementioned “Deities of the Five Planets and Twenty-Eight Constellations” also depicts the planets in similar garb, though they ride animals rather than wearing animal caps:
To summarize, I want to emphasize that Buddhist traditions, both in India and East Asia, were full of astrological lore, beliefs and practices. This influenced both religious practices as well as the art record. Planetary invocations and star worship, it seems, were quite common during the so-called "golden ages" of Buddhism in both India and China. I have not investigated Tibetan Buddhism in this respect closely, but I can refer readers to Edward Henning's quality work on the subject of astrology in Tibet (see here). I have seen for myself how important astrology is for many Lamas and monks around India and Nepal, and they've assured me how popular it is. It seems historically this was just as much the case as well.
In an upcoming paper to be formally published I will discuss how originally Buddhism and perhaps the Buddha himself dismissed astrology and prohibited monks from practicing it. The paradox, of course, is that historically many Buddhists did in fact practice astrology despite such prohibitions and refutations of astrology. The history of all this is rather complex and hopefully within a few years my dissertation on the subject will be finished and I can share it with everyone.
Barton, Tamsyn. Ancient Astrology. New York: Routledge, 1994.
Chan Man Sing 陳萬成. "Du Mu yu xingming" 杜牧與星命. Tang yanjiu 唐研究 8 (2002): 66-68.
David Pingree. “Identification of the Yogatārās of the Indian Nakṣatras.” Journal for the History of Astronomy 20 (1989): 99-119.
Pankenier, David. Astrology and Cosmology in Early China Conforming Earth to Heaven. Cambridge: Cambridge University Press, 2013.
Yano, Michio. “Calendar, Astrology, and Astronomy.” The Blackwell Companion to Hinduism. Oxford: Blackwell Publishing, 2003.
Yano, Michio 矢野道雄. Mikkyō senseijutsu 密教占星術. Tokyo: Toyoshoin, 2013.