Sky as a bridge:Transmission of Indian astronomy

to China, Korea and Japan

Rajesh KochharPresident IAU Commission 41: History of Astronomy

Hon. Prof. Panjab University Mathematics Department ChandigarhIndian Institute of Science Education and Research, Mohali, Punjab

rkochhar2000@yahoo.com

ICOA-8 Hefei, China, 26-28 March 2014

Ancient cultural tradition of the Indian

subcontinent (India for short) is

characterized by a combination of three

important factors: (i) antiquity, (ii)

continuity, and (iii) interaction with the

outside world.

There are two distinct phases in Indian

astronomy: (i) Vedic astronomy and (ii)

Siddhantic astronomy.

The oldest astronomical text in India is

Vedanga Jyotisha the earliest portions of

which could be as old as 1400 BCE. Indian

astronomy remained static for a very long

time.

From 1st century BCE to 5th century CE new

Greco-Babylonian inputs were received from

the northwest. These included an accurate

luni-solar calendar (the Shaka (Saka) calendar

) and concepts of zodiac and week days.

The pioneering name in the modernization

of Indian mathematical (or Siddhantic)

astronomy is Aryabhata (b. 476 BCE) who

composed his concise but influential work

Aryabhatiyam [simply meaning

Aryabhata’s] in 499 CE.

Siddhantic astronomy focused on

calculating eclipses and planetary orbits.

In a tradition spanning more than 1000

years India produced a number of

eminent mathematician- astronomers

who set up and solved new equations,

and suitably adjusted the parameters so

that calculated planetary positions could

match the observed sky. /

India’s interaction with East Asia was on two

distinct lines.

Interaction with China, and through it with

Korea, Japan and Vietnam, was driven by

Buddhism and characterized by translation of

Buddhist and other texts.

Buddha personally was firmly against

astrology, but by the time Buddhism was

exported to East Asia, astronomy/ astrology

had become part of it. Unlike the

traditional Chinese focus on portents,

Indian mathematical astronomy could

prepare horoscopes for the benefit of

individuals.

Transmission to China

Transmission of astronomy to China began

in the 1st century CE during the Later Han

period (25–220 CE) and continued into the

politically unstable Three Kingdom period

(220-265 CE).

Indian inputs to China continued

intermittently even after that, with the most

detailed incorporation of Indian astronomy

coming during the Tang Dynasty (618-906

CE).

It needs to be appreciated that Indian

and Chinese histories of astronomy are

interlinked. An investigation of India-

inspired developments in Chinese

astronomy requires familiarity with the

state of astronomical knowledge in India

at that time.

At the same time China is important for

obtaining a better understanding of

developments within India.

This is so because India’s own

sources have inherent

limitations. Reference to

Chinese sources may help

overcome them to an extent.

Nature and limitation of ancient Indian

source material

India’s intellectual tradition has been

oral. Permanent writing material was not

used. And there was no system of

counting years.

Astronomy texts were not designed as self-

contained self-study library books. Their

comprehension required familiarity with the

context and help of commentaries which in

many cases are no longer extant.

Astronomical results were recorded in terse

metrical poetry, in imitation of the sacred

Rigveda. However unlike the sacred texts

which were frozen in time, astronomy (and

healthcare) texts underwent constant

revision. A text not considered relevant at

any time would be forgotten for ever,>

except for excerpts incorporated in other

texts. Some time only the names of texts

or authors have been preserved without

any other information.

Chronology remains a severe handicap in case of

ancient Indian literature. Astronomy fares a little

better than other disciplines because time in

inbuilt into astronomical calculations. Still, there

are many texts and developments which cannot

be dated.

In other words, it is not possible to construct a

connected historical account of ancient astronomy

(or science in general) in India. Celebrated texts

record the end results but various stages of

development preceding them may not be known

at all or known only sketchily.

Buddhist intellectual tradition followed a

different route. Buddhists wrote down their texts

and preserved them. In many cases they can be

assigned reliable time bracket, by reference to

external sources.

Thus East Asian records with firm dates can

help fix the chronology of Indian

developments which Indian sources

themselves may not be able to do.

Instructive illustration of this come from

healthcare.

The celebrated medical texts, Charaka.samhita and

Sushruta.samhita, are known to India only in their

final definitive un-dated form. We know about state

of Indian healthcare in India in 4th century CE from

the well-known Bower manuscript which came from

Kucha, now a county in the Aksu prefecture in mid-

western Xinjiang province.

Also, an influential Indian healthcare text

Ashtanga.hrdya.samhita composed by

Vagabhata can be confidently dated 7th

century or a little earlier on the basis of

implicit reference to it in the work of the well-

known Chinese pilgrim I-tsing who was in

India from 672 CE till about 688 CE.

A valuable aid in the discussion of the

text’s contents is its Tibetan edition

prepared between 1013-1055 CE (Vogel

1965, pp. 8, 18). Vagbhata is the first

Indian physician to assign astronomical

causes to illnesses.

Vagbhata claimed that diseases which

originated during different stellar

(nakshatra) conjunctions followed

different courses. It would be interesting

to see how the Tibetan edition handles

this statement.

Rahu and Ketu: Changing meaning

In ancient times, the planets with their

predictable orbits represented cosmic order

and were a source of comfort. On the other

hand, phenomena like comets and meteors

appeared without warning and thus

represented divine wrath.

Ancient Hindu and Buddhist sacred literature

treats eclipses as a calamity caused by a demon.

He is called Svarbhanu in the Rigveda, but later

texts use the name Rahu. The Pali Buddhist texts

tell us that the Moon and the Sun freed themselves

from the grasp of Rahu by invoking Buddha’s

name (Chandima Sutta, Samyutta-nikaya 2.9; Suriya Sutta,

Samyutta-nikaya 2.10).

Similarly the Buddhist Sanskrit text Shardula.

karana.vadana, a portion of which was translated

into Chinese in 265 CE, treats Rahu as a

calamity.

For later reference we may note that

the term ketu was used as a common

noun to

denote a number of phenomena

involving light and smoke. It could thus

refer to comets and meteors.

Mathematical theory of eclipses was propounded

in India in 499 CE by Aryabhata. According to

this theory, solar and lunar eclipses occur when

the Moon is at either of its orbital nodes. These

theoretical points move in a direction opposite to

that of the planets and complete an orbit in the

rather short period of 18.6 years.

One would have expected the astronomers to

declare that since the cause of eclipses was now

understood, there was no need for a demon.

However to maintain continuity with the sacred

tradition, the demon was not banished but made

mathematically amenable. It now did not appear

suddenly but came by appointment!

The mathematical theory of eclipses was

immediately taken note of in astrological

literature, by Varahamihira. The two nodes were

classified as planets, implying that they were now

amenable to mathematics. Since they were

hypothetical they were dubbed shadow planets.

They could have been given entirely new names.

But to maintain continuity with sacred

literature, old terms were given new

meaning.

The name Rahu, already associated with the

eclipses, was given to the ascending node.

Another name was needed for the

descending node.

The old common noun ketu was picked up for

the purpose ( why, we do not know).

The two nodes are 180 degrees apart so that

specifying one fixes the other. It would thus have

sufficed to include just one of them. Both were

listed as planets no doubt to bring the planetary

number up to nine which was considered sacred.

To sum up so far, 6th century CE onwards,

Rahu and Ketu represent shadow planets.

Ketu is in addition used to denote meteor/

comet. Before 6th century CE, ketu is only

comet/ meteor while Rahu is the eclipse-

causing demon.

Chinese sources

Rahu as Luo-hou makes its first appearance in the

translated Matanga-sutra, that is Mo-deng-jie-

jing, which was rendered into Chinese by Zhu

Lu-yan and Ziu-Qian in 230 CE (sutra numbered

1300 of Taisho Tripataka).

According to Lee and Chen (2000), ‘In

this sutra, Luo-hou and “comet” are the

two hidden ones of Nine luminaries

(jiu-yao)’.

I suspect this interpretation is anachronistic. The

term nine luminaries should not appear before 6th

century CE.

A literal translation of the original Chinese

passage would be most welcome. It can then be

compared with the Sanskrit original

Shardulakaranavadana.

China’s systematic introduction to Indian

astronomy began in the early 8th century.

Remarkably, the Indian inputs did not reamin an

add-on, but were successfully assimilated. ( See

various papers by Michio Yano.)

An astronomer of Indian descent Qutan

Xida [Gautam Siddha] prepared an

astronomical treatise, Jiu-zhi-li in 718

CE. The elements of this Treatise in turn

were employed by the well known Chinese

astronomer Yi-Xing (687-727 CE) in his

famous calendar Da-yan-li.

Astrological treatise of the Kaiyuan Period is also

attributed to Qutan Xida. Consistent with the Indian

tradition Jiu-zhi-li designates Rahu as the ascending

node and Ketu the descending.

For some reason, Shen Kuo (1031-1095) in his

Meng-Xi Bi Tan interchanges the nomenclature of

ascending and descending nodes.

Far more significant was the contribution of

Indian Buddhist monk, Jin Ju Zha. His

work ‘Formulae forwarding of calamities

according to the Seven Luminaries’

contains detailed ephemerides of Rahu and

Ketu . These

were incorporated into the calendrical

calculations of the Tang dynasty Yuanhe

era, Year I ( 806 CE).

As already noted, naming the two nodes

separately is not necessary because they are

180 degrees apart. Jin Ju Zha’s work

recognizes this and introduces a

modification.

While employing Rahu to denote the ascending

node, he boldly decided to use Ketu to denote

lunar apogee (Niu 1995).

This is significant because in Indian

astronomical texts ( as distinct from

the astrological ones) the term ketu

does not appear. This is for good

reason.

Once ascending note had been fixed there was no

need to discuss the descending node. Since

meteors/ comets were not predicable phenomena

ketu in the other sense would be irrelevant in a

Siddhantic text.

The Chinese use of the term ketu in a

mathematical sense was thus an

innovation.

An influential astrological text in China was

Hsiu-yao ching ( ‘the canon of mansions and

planets’) translated from an Indian work by

Amoghavajra in 759 CE. A more detailed

account was given in the 9th century treatise

Ch’i-yao jang-tsai-chuch (‘formulae for avoiding

calamities according to the seven luminaries’).

Taisho Tripitaka compiled by the Japanese

during 1924-1934 CE is the most popular edition

of the Sanskrit sutras translated from Sanskrit

into Chinese from late 2nd till 11th century CE.

Niu Wei-Xing has published extensively on

astronomy in these sutras.

While interpreting Indian influences in

Chinese astronomy, scholars should not fall

in the anachronistic trap. First of all as literal

a translation as possible of the original

Chinese text should be provided. Next, the

interpretation of Chinese sources should be

attempted in the framework of knowledge

prevalent in India at that time and not later.

Let me say a few lines about Buddhist

cosmology which in fact needs a

separate detailed treatment.

Cosmology

Buddhist cosmology was inspired by India’s

geography. At the centre of the Earth stood

Mount Sumeru around which revolved the

geocentric planets and the cosmic sphere.

Sumeru was thus an abstraction of the

Himalayas and the Earth’s spin axis.

In conclusion

From the point of view of Indian

history scholars would be interested in

obtaining help from China on two

important counts.

(1) What can we learn from Chinese

sources about Indian astronomy prior to

Aryabhata (499 CE). ( As I mentioned, very

little is known about transition from the

Vedic astronomy to the Siddhantic.)

(2) What gaps can be filled with help

from Chinese sources in the

development of post- 499 CE

Siddhantic astronomy?

References

Kochhar, Rajesh (2010) ‘Rahu and Ketu in mythological

and “astronomological” contexts.’ Indian Journal of

History of Science, Vol. 45, No. 2, pp. 287-297.

Lee, Eon- Hee and Chen, Kwan-Yu (2000) ‘A study of the

motions of Rahu and Ketu.’ Proc. 3rd Intl Conf on

Oriental Astronomy (ed: M. Hirai), pp. 93-96 ( Fukuoka:

Fukuoka University of Education Press).

Nakayama, Shigeru ( 1969) A History of Japanese

Astronomy: Chinese Background and Western Impact

(Cambridge: Harvard University Press).

Niu, Wei-Xing (1995) ‘An inquiry into the

astrological meaning of Rahu and Ketu.’ Chinese

Astronomy and Astrophysics, Vol. 19, No. 2, pp. 259-

266.

Niu, Wei-Xing (1997/98) ‘Astronomy in the sutras

translated into Chinese.’ Studies in the History of

Medicine and Science, Vol. 15, No. 1-2, pp. 119- 129.

Vogel, Claus (1965) Vagabhata’s

Astangahrdyasamhita: The first five chapters of its

Tibetan Version ( Wiesbaden: Deutsche

Morgenlandische Gesellschaft).

Thank you