Pramāṇa · Search · About · API

Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s5: Chapter IV: On Observations

Bhāratīya Jyotiḥśāstra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s5

Language
English

Contents

Chapter IV: On Observations

v2.c12.s5.2

General Description

v2.c12.s5.3

The word ‘vedha’ is derived from the root ‘vyadha’. Vedha is the name given to the act of observing the sun or anyother celestial body by holding a rod or a stick or some other object in between. Because the luminous celestial body is ‘struck’ by the rod, the act of observation has received the name “vedha”. The simple casting of a look at a celestial body is termed ‘avalokana’ (sighting); but this act also can be termed ‘observation’. Let us call this kind of observation ‘dṛṣṭivedha’ (i.e. look). The observation which is taken with the help of a stick or other means of taking observation, commonly known as ‘instruments’, should be termed ‘yantra-vedha’ (i.e. instrumental observation).

v2.c12.s5.4

Our Tradition favours Observation

v2.c12.s5.5

Europeans say that our people have no knowledge of observation, that our country lacks the tradition of taking observations, and that they have no instruments for taking them; and they put forth this plea as the main ground for their contention that the Hindus borrowed the science of astronomy from the Greeks. Certainly it cannot at all be said that our people have no liking for observing natural phenomena or that they have no such tendency. This has been proved on the basis of many things pointed out in Part One. Thus the 27 nakṣatras, were known to us even in the dim and distant past, the Vedic times. The Rigveda refers to Saptarṣi stars and the planets. The Yajurveda describes the 27 nakṣatras at great length. In addition to this, the author has pointed out allusions to the constellations known as the pair of divine dogs, the divine boat, and the Prajāpati controlling the nakṣatras. The Taittirīya Saṃhitā narrates a lengthy story about the extreme love of the Moon for Rohiṇī, and the origin of the story is found in the phenomena of the Moon’s close conjunction with the star Aldebaran, and the latter’s occultation by the Moon, which occurs repeatedly in a period of six years out of every nineteen. The Āśwalāyansūtras allude to Dhruva and Arundhati. We know of the phenomenon of saturn splitting the car of Rohiṇī 7000 years ago. The Mahābhārata abounds in the description of planets, comets and stars, and the instances have already been cited before. Even the Rāmāyaṇa of Vālmīki refers to the planets and stars at many places. Clusters of stars are mentioned in the Yājñavalkya Smṛti. Our liking for the observation of phenomena becomes evident from these several references occurring in works which are not purely astronomical. Again, there is no doubt that some at least out of the saṃhitās compiled by Garga and others belong to a period prior to that in which our astronomical system was firmly established. They mainly deal with the question of “grahacāra” i.e. the movements of planets through the nakṣatras. Varāha Mihira has in a long chapter entitled Ketucāra described a good many comets. In the beginning of the chapter, he observes,‘ गार्ग्यं शिखिचारं पाराशरमसितदेवलकृतं च ।। अन्यांश्च बहून् दृष्ट्वा क्रियतेयमनाकुलचारः which means that he was describing the comets on the basis of the descriptions given by Garga, Parāśara, Asit, Deval, and many other sages. The author is giving below some of the quotations from Parāśara and others, cited by Bhaṭotpala in his commentary on the above verse :—

v2.c12.s5.6

पैतामहश्चलकेतुः पंचवर्षशतं प्रोष्य ददितः ।। ……… अथोदालकः श्वेतकेतुर्दशोत्तरं वर्षशतं प्रोष्य……… दृश्यः ।। ………शलाग्राकारं शिखां दर्शयन् ब्राह्मणक्षत्रमुपसृत्य मनाक् ध्रुवं ब्रह्मराशिं सप्तर्षीन् संस्पृश्य ………काश्यपः श्वेतकेतुः पंचदशं वर्षशतं प्रोष्यैतां पद्रकेतोश्चारांते ……… नभसस्त्रिभागमाक्यापसव्यं निवृत्त्यार्थप्रदक्षिणजटाकारशिखः स यावंतो मासान् दृश्यते तावद्वर्षाणि सुभिक्षमावहति ।। ……… अथ रश्मिकेतुर्विभावसुजः प्रोष्य शतमावर्तकेतोरुदितश्चारांते कृत्तिकासु धूमशिखः ।।

v2.c12.s5.7

पराशर.

v2.c12.s5.8

Purport.—The Paitāmaha comet re-appears after travelling for 500 years (i.e. disappears for 500 years, after it is first seen and then appears again). The comet named Uddālaka Śvetaketu appears after travelling for 110 years. The comet Kāśyapaśvetaketu whose tail is pointed like a spear, and who, after the disappearance of the comet Padmāketu, first appears in the East, after having travelled for 1500 years, and who, after contacting the Brahma (Abhijit) constellation, the Pole star, the Brahmarāśi* and the Great Bear, traverses the third part of the sky, turns to the left and gives plenty of crops for as many years as the number of months it remains visible in the sky, with its semi-circular tuft of hair. Vibhāvasujarāśmiketu, after having travelled for 100 years, makes its appearance near the Kṛttikā stars after the Āvartaketu. It has a tail of smoke.

v2.c12.s5.9.1

Descriptions of many such comets are available. The comets may have received the names Uddālaka, Kāśyapa etc. after the Ṛṣis who discovered and investigated the nature of these comets. This is just like what we find at present in the case of comets such as Enki’s comet, Halley’s comet, etc. named after European astronomers; and these descriptions appear to have been given on the basis of researches traditionally carried on through centuries. The statements of Āryabhaṭa and Brahmagupta that they determined the positions of the Sun and Moon after observing the eclipses have already been given. If the work of taking observations is carried on continuously for several years, it gives useful results; and it is not possible to do this without royal patronage. Varāhamihira has described how astronomers deserve respect. He has also written that kings should employ astronomers in their service, that some of them should be engaged in the task of taking daily observations of the sky, and that they should distribute amongst themselves different parts of the sky, and then take observations. From this and from the astronomical works, Rājamṛgāṅka Karaṇa by King Bhoja, and Karaṇa Kamala Mārtaṇḍa by King Daśabala of Vallabha dynasty which have been mentioned before and from the fact that several authors of astronomical works had the patronage of kings, as can be seen from their own account, it appears that the work of taking observations used to be carried on by royal support.

v2.c12.s5.9.2

Corrections recommended by different astronomers to be applied to the mean places of planets have been given before at several places. It is evident that these could not have been devised at random. Keśava, for one has described the observations actually taken by him (page 129). KAMALĀKARA the author of Siddhāntatattvaviveka has declared that the pole star has a shifting motion. Even in these days we come across persons who have a liking for observing things. One finds several persons who can correctly point out the planets and several stars even though they have not studied astronomy. Thus two persons who had absolutely no knowledge of English, Sanskrit and astronomy once casually told that the pole star is not stationary ; and one of them was very fond of observing stars, risings and settings of planets and their conjunctions, and he was very helpful to the author. Once a Vaidic Brāhmaṇa named Pādhye, a resident of Āgāśī, casually met the author in Poona in Śaka 1809. He had not studied any system of astronomy. Still, he chanced to state that, while most of the stars moved from east to west, some stars (those near the North Pole) move in a reverse direction, that is from west to east ; and he told that he came to know of it from his brother Nārāyaṇa Janārdan Pādhye. That brother died in Śaka 1795. At that time he was about 22 years old. He was surprisingly intelligent. There may be several such people living. The experiences related here may appear very trivial to some ;

v2.c12.s5.9.3

but man must have acquired knowledge of astronomy in the initial stages, through the efforts of such persons ; and my object in relating such experiences is to show that the habit still persists among our people. Europeans are surprised to see that while the Saura, Ārya and Brahma siddhāntas mention the numbers of revolutions and other elements of planets, no hint is anywhere given as to how these were calculated and no information of the observations taken has been recorded in them. But they do not take into considaration the conditions in ancient times and the beliefs of our people. In those times when even scripts or any means of writing, not to speak of the printing presses, were not easily available or were even non-existent and all knowledge was preserved by the tradition of being vocally imparted by the teacher to his disciples. Hence, it was but natural that only the siddhāntas which embodied the results of research survived while their sources perished. Again, nobody will now feel astonished if one predicts the time of the occurrence of an eclipse. But in ancient times a man who could predict these phenomena was naturally considered to be superhuman. If he compiled a work, he would naturally incorporate in it only the resulting principles without mentioning their preliminary forms or the means employed in arriving at them. Then in course of time, the work would possibly come to be regarded as ‘apauruṣeya’ (divine) after the author’s name is forgotten & lost ;

v2.c12.s5.9.4

and once this practice secured a firm footing, the future authors of ‘human’ works abstained from mentioning the preliminaries leading up to the final results. These were quite probably the reasons why our ancient works lack the information about the observations taken, similar to what we find recorded in Ptolemy’s works about his own observations and those taken by Hipparchus, or in the works of later western astronomers. However, some information about the individual efforts made in respect of observations has already been given and some more will be given further on.

v2.c12.s5.10

∗ The word Brahmarāśi occurs in Chapter III of Bhīṣmaparva in Bhārata, as can be seen from the extract given in Part I (page 117). It seems from this and also from the above reference, as also from the fact that Brahma was the deity controlling the Abhijit nakṣatra, Brahmarāśi was the name given to cluster of stars around the Abhijit star and the description of the place occupied by the comet agrees with what one may find on the celestial globe. There is nothing impossible in this; particularly the semicircular shape of the hair (described in the passage) tallies exactly with the position with respect to stars in the sky.

v2.c12.s5.11

DESCRIPTION OF INSTRUMENTS

v2.c12.s5.12

The instruments for locating the positions of planets and those for measuring time will now be described. The works compiled by Bhāskarācārya are widely known. Hence, it will be of convenient first* to describe the instruments mentioned by him and then to give a brief account of what we find in other works.

v2.c12.s5.13

GOLA YANTRA

v2.c12.s5.14

OR (Armillary Sphere)

v2.c12.s5.15

A straight round stick of uniform thickness should be taken. It may be called “pole-stick” (dhruva-yaṣṭi). A small spherical ball which can easily slide should be fixed in it, in the centre, to represent the earth, Then a (concentric) sphere to represent the starry sphere should be fixed all round it, It should represent the celestial sphere in which the Sun and other planets are seen to move round the earth. The construction of the starry sphere (bhagol) is as follows :—

v2.c12.s5.16.1

Prepare an exactly circular ring**. It should be so tied at two points to the pole stick that it will be divided by those points into two exact parts. A second ring of the same size should be tied to the stick, so that it will cut the stick in those two points, will be perpendicular to (the plane of) the first ring, and will itself be bisected at the two points. These circular rings are called the pair of “standard great circles”. Tie a third ring to these rings at four points so that it will be at right angles to them both, and the pole stick will be its axis. This ring is termed ‘Nāḍīvalaya or Viṣuvavṛtta’. Divide this ring into 60 equal parts to represent nāḍīs (or ghaṭikās). A circular ring of equal circumference, called ‘Krāntivṛtta’ or the ecliptic circle should be tied to the ‘equator-circle’ cutting it at two points and inclined to it at an angle of 24°. The Sun moves in this circle. It should be divided into 12 equal parts to represent the signs. If the ball representing the earth be supposed to be a planet other than the sun, ‘great’ circular rings should be tied to the ‘ecliptic-circle’ at angles equal to the inclinations of the orbital planes of the planets. These also should be marked to show the signs. Then circular rings showing diurnal circles should be tied to the ecliptic circle.

v2.c12.s5.16.2

While tying the circular rings, care should be taken to see that a portion of the stick is kept projecting and these ends should be passed into two tubes fixed in the celestial sphere whose construction is described later on. The ends of the polestick should point to the poles of the equator, so that the north end of the stick should be found to make an angle, equal to the latitude of the place, with the north pole of the equator lying in the celestial globe which is fixed clearly all round the ‘starry sphere’; and the ends of the pole stick should be so passed into tubes that, while the ‘khagoi’ (celestial sphere) would be kept fixed in position, the starry globe would freely rotate in it. The celestial globe should be so set as to envelope the starry globe. Its construction is as follows. Its circular rings should, of course, be larger in size than those of the starry globe. The ring representing the ‘samavṛtta’ (prime vertical) which passes through the zenith, nāḍir, and the east and west points, similarly the ring representing the meridian, as also the other rings representing the secondary directions—all these four rings should be of the same circumference. These should be tied to one another, so that each of them would pass above and below the others. The ring representing the plane of the horizon should be tied to them all, midway between them.

v2.c12.s5.16.3

The north pole should be set above the horizon at an altitude equal to that of the latitude and the south pole at an equal depression below it. Prepare a ring representing the ‘Unmaṇḍal’ (six o’clock circle) i.e. the great circle which would pass through the east-west points and both the poles which are points in the meridian circle to which the ends of the pole stick in the starry globe are directed. Then tie a ‘nāḍivalaya’ (celestial-equator-circle) which lies in the plane of the equator of the starry globe and which is larger in size. This should be graduated into ghaṭis. Then fixing nails at the points representing zenith and nāḍir, another ring should be so fixed in position that it would be free to rotate in a vertical plane with the two nails as the pivots. This is to be called a ‘dṛṅmaṇḍal’ (i.e. the vertical circle for observation). As this is to be rotated inside the celestial glove it should be somewhat smaller in size. A planet is to be observed after so rotating the vertical circle that the planet would be seen in the plane of the observation circle. This celestial globe should be so fitted around the ‘starry globe’ that the ends of the pole stick could be made to pass through the two tubes fitted on to it. Then after fixing two tubes in the ‘khagol’ from the outside, another globe called driggola should be fitted on; and all circular rings like those in the ‘khagol’ and ‘bhagol’ should be fixed on to it.

v2.c12.s5.16.4

This globe is to be constructed so as to enable one to have a proper understanding of the arcual lines like ‘agra’ (amplitude) ‘kujya’ (the radius of the earth) etc., which require the reference to two globes. The whole structure is now Called a ‘gola’ (i.e. a globe). (Our astronomers sometimes used the term “kṣetra”, to denote lines.)

v2.c12.s5.17

∗ This description has been given from the chapters on Golabandha and Yantras (istruments). If an attempt be made to describe in detail the instruments along with an explanation of their names, such as Nāḍīvalaya, and other terms, much space will be occupied, and even with all that, it is very difficult to present a description that would enable one to understand them properly without actually seeing them. Hence, only a brief description has been attempted. These however, will help even a layman to understand well the chapters on Golādhyāya and Yantrādhyāya by Bhāskarācārya. If all these instruments are made in the Chhatre memorial scheme, they will prove very useful at a moderate cost.

v2.c12.s5.18

∗∗ Straight, pliable, and soft bamboos have been recommended for preparing these rings. Even those made out of wire will do. These rings themselves represent circumferences of circles.

v2.c12.s5.19

The orbits of planets should, if necessary be tied in this globe separately with circles of aphelia and perihelia. This globe has been described to show the construction of the Universe. In fact it is very difficult to tie together all these rings, and it is still more difficult to take observations with their help. for instance, if the starry globe is fixed inside a ‘khagola’, it will be difficult to fix the observation circle. It cannot be believed that Bhāskarācārya and others could not realize these difficulties. It is clear that at the time of taking actual observations only the most necessary rings should be made use of, and observation can thus be taken. We had no instrument of the type of astrolabe designed by Hipparchus; but this speaks for the independence of our works in this respect. The above globe can be used in place of the astrolabe, Brahmagupta, Lalla, and both the Āryabhaṭas have recommended the construction of the same kind of globe. The globe described by the First Āryabhaṭa is less complicated than this.

v2.c12.s5.20

Bhāskarācārya has mainly described nine kinds of instruments, and their chief use is to find time; but three of them can be used mainly for taking observations of the celestial bodies. I shall here describe all of them briefly.

v2.c12.s5.21

1. *The Cakra Yantra* (The disc instrument):— Procure a disc* of metal or wood. Make a fine hole at its centre. Provide some pivot to the rim of the disc, to which a chain etc. can be attached to support the instrument with. Mark on the disc a line passing through the pivot and the central hole : (this will always remain vertical when the instrument is held suspended in position). Mark on it another line perpendicular to the first line and passing through the centre. Mark graduation lines on the circumference of the disc to indicate degrees. Pass a rod through the hole, perpendicular to the disc. It will serve as an axis. Hold (in hanging position) the disc, with the help of the support before the Sun in a vertical plane, so that the axis will cast a shadow on the disc. The degrees counted from the point in which the shadow cuts the rim to the point in which the horizontal line cuts it, will give the altitude of the sun, and the degrees counted from the point to the lowermost point of the disc, will give the zenith distance. (The time of the day can be calculated from this). The same disc may be so held that any two of the ‘zero-latitude’ stars, Puṣya, Maghā, Śatātārakā and Revatī will be found to be in the plane of the rim. (The disc will thus be held in the plane of the ecliptic). Then the planet will be sighted by moving the eye to and fro, so that the axis would intercept the sight; the longitude and latitude of planets can thus be found. It is in a way similar to the ‘aṇmaṇḍal’ of the Gola Yantra.

v2.c12.s5.22

2. *The Cāpa* (Semi circular disc) :— The half part of the Disc instrument is called a ‘Cāpa’ instrument.

v2.c12.s5.23

3. *Turyagola* (Turiya Yantra) :—Half part of the ‘Cāpa’ instrument i.e a ‘quadrant’ forms a Turiya instrument.

v2.c12.s5.24

These three instruments are chiefly used in taking observations.

v2.c12.s5.25

4. *The Gola instrument* (Globe instrument) :—Placing a ‘bhagola’ in a ‘khagola’, mark a spot on the ecliptic ring at a place where the sun is expected to be on a particular day. Then so rotate the ‘bhagola’ that the mark will cut the horizontal circle. Mark that point in the horizon in which the plane of the equator in the ‘bhagola’ will appear to cut. Then again rotate the ‘bhagola’ so that the spot marking the Sun’s position will cast a shadow on the ‘bhugola’ i.e., the terrestrial globe. Where the shadow is cast, the number of ghaṭis indicated between the spot and the ‘nāḍivalaya’ will give the number of ghaṭis elapsed after sunrise on that day. Then the point of the ecliptic in contact with the horizon will give the ascendant at the moment.

v2.c12.s5.26

5. *The Nāḍivalaya* :—Procure a circular disc. Graduate its rim in ghaṭikās. Pass a rod through its centre perpendicular to the disc. When the rod is held, pointed to the pole, it will cast a shadow on the rim ; and from it the hour angle (natakāl) or its complement can be read. If this very disc is so fitted in a globe that the pole stick will pass through its centre and the terrestrial globe will occupy the central position in it, and if marks indicating ghaṭikās, rising of signs, and the sixfold division of signs (lagna ; horā ; dreṣkāṇa ; navāṃśa ; dvādaśāṃśa & triṃśāṃśa) are made on it, then the shadow cast by the stick will help in finding the time elapsed and the sixfold divisions.

v2.c12.s5.27

6. *The Ghaṭikā* Instrument :—This is too well known.

v2.c12.s5.28

7. *The Śaṅku* (Gnomon) :— Śaṅku is a piece of a round, straight and uniformly thick rod 12 ‘anguls’ in length and having its ends plane and uniform. The chapter on three problems describes methods of finding time etc. from the shadow cast by it.

v2.c12.s5.29

∗ *The description will show that it is not a wheel but a disc cut out from a sheet (of metal).*

v2.c12.s5.30

8. The Phalak Instrument :—It is an instrument for finding time designed by Bhāskarācārya on the principles of the Cakra Yantra. Its details are not given here for want of space.

v2.c12.s5.31

9. Yaṣṭi Yantra (Pole instrument) :—

v2.c12.s5.32

Draw a circle with any radius on an even horizontal ground. Mark off principal directions on it and then draw arcs showing ‘agrā’ (amplitude of the day), both in the East and the West. Draw another concentric circle smaller in size and having a radius equal to “dyujyā” (sky-radius). Mark off points on it to show 60 ghaṭis. Take a stick equal in length to the radius of the outer-circle and hold it pointing to the Sun, with its one end placed at the centre of the circle, so that the stick will cast no shadow. Place in the smaller circle a rod which is equal in length to the distance of the other end of the stick and the end of the amplitude marked in the east. The arc showing ghaṭis intercepted between the ends of the stick will show the time elapsed (in ghaṭis). If the sun is in the West, the distance between the ends will give the number of ghaṭis showing the time left for the day to end. The methods of finding a number of things like ‘palabhā’, with the help of the ‘Yaṣṭiyantra’ have been described. Brahmagupta and Lalla have described the method of finding the distance between the Sun and the Moon, and from that the tithi, with the help of a similar but somewhat different type of a ‘yaṣṭiyantra’.

v2.c12.s5.33

Bhāskarācārya has mentioned two other additional self propelled instruments for finding time.

v2.c12.s5.34

We find in Atharva Jyotiṣa, discussion of the shadow cast by a gnomon, which proves* that the gnomon was known to us before our science of astronomy came in contact with that of the Westerners. The Pañca Siddhāntikā contains a chapter on instruments, which is not quite intelligible ; still it appears that many of the instruments described by Brahmagupta and others were in use in those times. Āryabhaṭa I has not described any instruments at all, but has mentioned a globe as described above. He has, in addition, stated that a globe should be so prepared for finding time that it will automatically rotate with the help of mercury, oil, or water.** Take a wheel. Fix in it somewhat hollow spokes half filled with mercury, with their ends sealed. The wheel will then rotate automatically. Brahmagupta and Bhāskarācārya have mentioned one such automatic instrument. From the globe instrument of Āryabhaṭa described above and from the references in the Pañca Siddhāntikā to some wonders occurring automatically by means of the instruments, it appears that at the time of Varāhamihira there existed such instruments and some other kinds of ‘swayam waha’ i.e., automatically working instruments. Varāhamihira and Āryabhaṭa have not described the process of construction. Brahmagupta also has described, in addition to the above instruments, some other wonders happening automatically, but has not described their processes.

v2.c12.s5.35

Instruments of the same type or with certain variations as those described by Bhāskarācārya are met with in the works of Brahmagupta and Lalla. ***But both of them have mentioned some additional instruments for finding time, viz. Kartarī, Kapāla and Pīṭha. The modern S. S. does not describe any instruments in detail ; still it has mentioned the names of the following instruments :—Swayam-waha; Gola, Śaṅku, Yaṣṭi, Dhanu, Cakra and Kapāla. It is interesting to note that the Pañca Siddhāntikā, Āryabhaṭīya, modern S.S. and Lalla-tantra do not anywhere mention the ‘Turiya yantra’.* It was Ptolemy among western astronomers who first invented the quadrant instrument. Before his time, they used the complete circular instrument for taking observations ; but later on, the Western astronomers began to use the quadrant instrument for all purposes. In modern times, however, the quadrant instrument has completely disappeared and the complete circle instruments have come into use in their place. Modern scholars accuse Ptolemy of having taken a retrograde step by introducing the quadrant instrument.** The purpose of mentioning this here is that while the quadrant instrument has been mentioned by Ptolemy, it was not known to our astronomers till śaka 500. It, therefore, proves that the Romaka Siddhānta is neither a translation of Ptolemy’s work nor has it been compiled on the basis of that work and that we knew nothing about Ptolemy’s work, till at least Śaka 500. The same thing was seen before from our study of the Romaka Siddhānta (Page 12). One more important thing which comes to our notice is that all our instruments have been invented by our astronomers quite independently ; and the quadrant instrument which came into use later on, was also independently invented. It could have been easily suggested by the ‘cakra’ and cāpa instruments ; and since it occurs for the first time in Brahmagupta’s work, it must have been invented by him.***

v2.c12.s5.36

∗ (3) Atharva Jyotiṣa ”,

v2.c12.s5.37

∗∗ Āryabhaṭya, Golapāda, coāuplet No, 22.

v2.c12.s5.38

∗∗∗ Bhāskarācārya invented a new instrument called the Phalak instrument ; but its origin is to be found in the Cakrayantra itself. Out of the remaining eight, Brahmagupta has not explicitly mentioned the Gola & Nāḍivalaya as seperate instruments. He has, however, mentioned the Golabandha which includes the two. Lalla has not mentioned the Nāḍivalaya out of the eight instruments, but it is included in the Gola itself. It is, however, somewhat surprising that he has not mentioned the Turiya instrument.

v2.c12.s5.39

The second Āryasiddhānta and modern siddhāntas by Romaśa, śakalya, Brahma, and Soma do not contain the chapter on instruments at all.****

v2.c12.s5.40

ANCIENT OBSERVATIONS OF WESTERNERS

v2.c12.s5.41

It would not be irrelevant to say something here about the ancient methods of observations of the Westerners.† The Chaldeans, to whom the origin of astronomy is usually ascribed by European scholars, do not seem to have attained any excellence in this important department of the science. Their observations of eclipses of the moon, as cited by Ptolemy†† are as rude as can possibly be imagined. The time is expressed only in hours, and the quantity eclipsed in terms of the half & quarter of the moon’s diameter. Herodotus states that the Greeks were indebted to the Babylonians for the pole, the gnomon and the division of the day into twelve hours. The pole seems to have been

v2.c12.s5.42

*After detecting this omission, the author could not find time for reading the texts of these works minutely, particularly with an eye to the word “turiya”. I have, however, gone through all those portions of the works where that word could possibly have occurred and ascertained that it does not occur there.

v2.c12.s5.43

**Grant’s History of Physical Astronomy, p. 440.

v2.c12.s5.44

***The fact that no mention of the ‘turiya’ instrument has been made in the Sūrya Siddhānta is an additional proof to show that the work was compiled before Brahmagupta’s siddhānta.

v2.c12.s5.45

****That does not, however, prove that these Siddhāntas were compiled earlier than the Sūrya and other siddhāntas.

v2.c12.s5.46

†This paragraph has been written on the basis of Grant’s History of Physical Astronomy, Chapter XVIII.

v2.c12.s5.47

††Rehatsaik states that the most ancient of these observations are the three eclipses which occurred in the years 719 and 720 B.C. (Jour. B.B.R.A.S. Vol. XI).

v2.c12.s5.48.1

a concave hemispherical sun-dial, having a vertical style in the centre, by means of which the interval included between sunrise & sunset was divided into twelve equal parts. It is probable that by the use of the gnomon the Chaldeans succeeded in obtaining an approximation to the length of the solar year, but there is not the smallest reason to suppose that they employed it in determining any other of the fundamental facts of astronomy. Indeed, they do not seem to have made observations at all for the purpose of forming materials to serve as the groundwork of future reasoning. They simply contented themselves with noting the more remarkable phenomena as they occurred, and hence deducing a few rough conclusions of a general nature. It would appear, however, that by comparing together the Chaldean records of eclipses some of the Greek mathematicians ascertained with considerable accuracy several periods relating to the motion of the moon. The earliest astronomical observation as having been made by the Greeks previous to the establishment of the *Alexandrian* school, is a determination of the summer solstice by Meton, in the year 430 A.C. The instrument, termed a heliometer, which was used by Meton on this occasion was, in all probability, no other than a modification of the gnomon.

v2.c12.s5.48.2

The date of this solstice has been chosen for the epoch of the Metonic cycle of nineteen years.* A new era commenced in the history of astronomical observation when *Alexandria* became the capital of the civilized world. Under the liberal patronage of the Ptolemies a magnificent building was erected, in which were deposited circular instruments for determining the positions of the heavenly bodies, and every facility was given to astronomers for prosecuting a continuous series of observations. Timocharis and Aristillus are the earliest individuals mentioned in connexion with this school. These astronomers appear to have flourished about the year 300 A.C. Ptolemy (150 A.D.) cites several of their observations. Among these are the declinations of a few of the principal stars and the records of eclipses. It does not appear that they were acquainted with any method for determining the right ascensions of the stars. Eratosthenes (275 B.C. circa) one of the Alexandrian astronomers, determined the obliquity of the ecliptic to be 23° 51' 19". It is manifest that neither the distances of the stars from the equator nor the obliquity of the ecliptic could have been determined even roughly without the use of instruments. In treating of the obliquity of the ecliptic, Ptolemy describes an instrument for determining the meridional altitude of the sun.

v2.c12.s5.48.3

It was composed of two concentric circles, placed exactly in the plane of the meridian, one of which revolved within the other about their common centre. The inner circle carried two small prisms attached to the opposite extremities of a diameter, and when the sun was on the meridian, it was turned round until the shadow of the upper prism fell exactly upon the lower one. An index, affixed to the latter, then marked upon the graduated limb of the outer circle the meridional altitude of the Sun. It was, in all probability, by means of an instrument of this construction that Eratosthenes determined the altitude of the Sun at each of the solstices & hence deduced the obliquity of the ecliptic. Ptolemy cites a passage from Hipparchus which shows that at Alexandria they used to ascertain the passage of the Sun through the equinox by means of a circular ring of metal disposed in the plane of the equator—the shadow of the upper half being watched until it fell upon the inner or concave surface of the lower half. It is not by what means the earlier astronomers determined the declinations of stars. Whatever credit may be due to the earlier astronomers of the Alexandrian school for the sound principles of observation which they appear to have practised, it is to Hipparchus alone that the establishment of astronomy, as a science of calculation based upon observed facts, is to be attributed.

v2.c12.s5.48.4

He determined the length of the year to be—365d—14g—48p as against the former measure of 365d—15g.

v2.c12.s5.49

∗ Meton fixed 6940 as the number of days in a cycle of 19 solar years (Indian Eras by Cunningham, page 43). This makes the length of the year 365d 15gh 47 368pal. Calippus made an improvement in the Metonic cycle by discovering the cycle of 76 years by which the length of the year became exactly 365d—15gh (Indian Eras, p. 43). It is worth noting that none of our astronomical works have adopted these cycles or lengths of year.

v2.c12.s5.50

He invented the astrolabe with which he used to find the longitudes and latitudes of celestial bodies. No one before him had a correct knowledge of the sun’s apparent motion; and it was he who first compiled tables for calculating sun’s true place; these were not known to anyone before him. He recorded observations of the moon, and appears to have compiled tables for finding the true place of the moon. He recorded observations of planets also. The observations recorded by Hipparchus proved useful to Ptolemy in deducing the correction for moon’s longitude, called “evection” and to establish the rule for finding the planetary motions. It has already been stated that Hipparchus found the longitudes and latitudes of stars. Ptolemy was not skilled in the work of taking observations. He invented the quadrant instrument. It is nowhere mentioned in clear terms how all these astronomers used to find time. It appears that they used to measure time by the shadow instrument and the clepsydra (‘ghaṭī’ instrument). Sometimes they used to record what part of the ecliptic was transiting the meridian at the time of taking observations. The Arabs did not bring about any appreciable improvement in the instruments of observation; however, their instruments of observation used to be larger and better than those of the Greeks. The astrolabe used by them was much more complicated.

v2.c12.s5.51

The above account will show that none of the various lengths of the year described so far agrees with those established by our siddhāntas. It has been proved in the study of the five ancient siddhāntas, that though the original Romakasiddhānta may have been compiled on the basis of the work of Hipparchus, the Romaka was not the most ancient of our works and that there were works on mathematical astronomy even before the Romaka (page 2).—

v2.c12.s5.52

Now the author will describe our independent works relating to instruments and observatories :—

v2.c12.s5.53

*SARVATOBHADRA YANTRA* :—It appears from two verses quoted by Bhāskarācārya, as from this work, in the chapter on instruments in the Siddhānta Śiromaṇi, that he wrote a work of this name for describing instruments, but as the work is not available, it cannot be described how the instrument was constructed.

v2.c12.s5.54

*YANTRA RĀJA* :—There lived in Bhṛgupura an astronomer Madan Sūri by name. His disciple Mahendra Sūri compiled this work in Śaka 1292. There is at the beginning of the work a salutation to ‘sarvajña’ (i.e. the Knower of all things). From this it appears that this writer must have been a Jain. The work consists of five chapters viz. Gaṇita (mathematics), Yantraghaṭanā (principles of instrument making), Yantra racanā (construction of instruments), Yantrasādhanām (use of instrument), Yantra vicāraṇā (theory of instruments), and has in all 182 verses in it. MALAYENDU SŪRI has written a commentary on it, in which he says that Mahendra Sūri was the Head Astronomer at the Royal Court of Emperor FEROZE SHAH. The Samvat 1435 (Śaka 1300) has been adopted in many of the solved examples. In one case the Samvat 1427 has been taken and in another, Samvat 1447; and the commentator calls Mahendra Sūri his preceptor, This shows that he (Malayendu Sūri) was his direct disciple; and the date of compilation of the commentary also was about Śaka 1300. Sudhākara Dwivedī published this work at Vārānasī. The author observes in the very first chapter,

v2.c12.s5.55

कल्पतास्था बहुविधा यवनैः स्ववाण्यां यंत्रागमा निजनिजप्रतिभाविशेषात् ।। तान् वारिधनीव विलोक्य मया सुधावत् तत्सारभूतखिलं प्रणिगद्यतेत्र ।।

v2.c12.s5.56

“ The writer is presenting in this work the description of instruments which he has gleaned from various works on instruments written by Yavanas, just as nectar is taken out from ocean.”

v2.c12.s5.57

He has assumed 3600 as the radius and 23° 35′ as the maximum declination; he has given tables of sines, declinations and sky diameters for each degree and has given the length of the shadow cast by a gnomon of seven inches for each degree of altitude, varying from 0° to 90°. The commentator has given the latitudes of about 75 cities. The author of the work has given sāyana longitudes and latitudes of 32 stars which are useful for observation, and has mentioned 54″ per year as the precessional motion. It is not possible to describe the construction of the instrument, Yantra Rāja, briefly, and hence it is not given here. With the help of this instrument the following things can be found directly from observation :—the altitude, zenith distance, longitude and latitude of the Sun ; planets and stars ; distance in degrees between any two celestial bodies, the latitude of a place, the ascending sign and the time and length of the day. There is a commentary on this work written by Yajñeśwara in Śaka 1764.

v2.c12.s5.58

DHRUVA-BHRAMA-YANTRA :—PADMANĀBHA, son of Nārmada compiled this work. It has already been pointed out (page 126) that the date of this Padmanābha is about Śaka 1320. The work consists of 31 verses and has a commentary written by the author himself. This instrument known as Dhruvabhrama Yantra is meant to find time and it consists of a rectangular plank of wood, the length of which is double the width, and which has a chink bored in it parallel to the shorter edge; the constellation of Dhruva-matsya (polar fish) is to be observed through the chink. The author does not intend to describe here in the construction of the instrument meant for finding time. The author has described the “ Polar fish ”* in the following words :— “ There is a cluster of 12 stars round the North Pole. It is called the ‘ polar fish ’. It has two bright stars, one of which is regarded as its mouth and the other as its tail. One of these is on one side of the pole at a distance of 3° and the other lies at a distance of 13° on the other side.” The author has described the construction of an instrument by which time can be noted at night by observing the stars situated at the mouth and the tail. A method has been described for finding time by observing other stars at night and even the Sun during the day. Similarly, even the ascendant at any moment is found with the help of this instrument, and it evidently gives the sāyana ascendant. The mean altitudes of junction stars of 28 asterisms at transit as observed in latitude 24° N have been mentioned. It shows that the author may have been the resident of a place whose latitude is 24°.

v2.c12.s5.59

*See commentary on the 11th verse.

v2.c12.s5.60

YANTRA CINTĀMAṆI

v2.c12.s5.61

A mathematician named Cakradhara, son of Vāmana, compiled this work and it has a commentary written by the author himself. In addition to this, there is a commentary on the work by Rāma, son of Madhusūdana, a resident of Pārthapura. The author has not given his date, but as he has quoted in his commentary some lines from Bhāskarācārya's Siddhānta Śiromaṇi, and Rāma, the commentator, has mentioned Śaka 1547 as the date of his commentary, the work must have been written some time between Śaka 1100 and 1500. His words, "kṣitipālamaulivilasadratna grahajñyāgraṇī cakradharaḥ" meaning "Cakradhara, the leading astronomer, and who is a jewel in the crown of kings" shows that he had the patronage of some king. The work has four chapters containing 26 verses in all. Dinakara, son of Ananta belonging to śāṇḍilya gotra wrote a commentary on it with examples in the Śaka year 1767. Yantracintāmaṇi is a kind of quadrant instrument. The observations taken with this instrument give the longitudes of the Sun and the Moon, and also the longitudes and latitudes of five planets, the desired time, and the ascendant true for that momemt, and such other things. The planetary positions and the ascendant are sāyana.

v2.c12.s5.62

PRATODA YANTRA

v2.c12.s5.63

Gaṇeśa Daivajña, the author of the Grahalāghava, compiled this work on instruments. It contains 13 chapters. The author claims that even while riding a horse one can find time by observation with the help of this Pratoda yantra, and also the shadow cast by the gnomon at that time. Its construction is not described here for want of space. Sakhārāma and Gopinātha have written commentaries on this work.

v2.c12.s5.64

GOLĀNANDA

v2.c12.s5.65

This instrument was invented by Cintāmaṇi Dikṣit (page 174). He has written a work entitled Golānanda concerning the instrument. It contains 124 verses. It has chapters (adhikārs) on the construction of the instrument, mean places, true places, three problems, eclipses, shadow, risings and settings of planets, observations and conjunctions. The following things can be found from observations taken by the Golānanda instrument :- Equation of centre to be applied to planets, planet's distance from the earth, true motion, declinations, ascensional difference, ascendant, directions, amplitude, zenith distance, valan (deflections), parallax, nati (parallex in latitude), latitude, drkkarma and the desired time. There is a commentary on the work entitled Golānandānubhāvikā by Yajñeśwara.

v2.c12.s5.66

There may be several such works on instruments. Rāma, the commentator of Yantra Cintāmaṇi, observes :-

v2.c12.s5.67

विलोकित्तानि यंत्राणि कृतानि बहुधा बुधैः ॥ मतः शिरोमणिस्तेषां यंत्रचिंतामणिर्मम ॥

v2.c12.s5.68

"I have seen almost all instruments prepared by learned men, and it is my belief that this 'yantracintāmaṇi' is the best of all." This shows that several kinds of instruments were in use.

v2.c12.s5.69

The instruments described in Siddhāntasiromaṇi and other independent instruments mentioned above are rarely seen constructed by any one at present. The gnomon and the quadrant instrument are found at some places. Some instrument by which the time of the day can be found is seen at a number of places.*

v2.c12.s5.70

OBSERVATORIES

v2.c12.s5.71.1

Let us now consider the question ofobservatories. It is evident that if the instruments of observation are permanently fixed they will be found more useful for observation. A building is specially erected for this purpose, and instruments are fixed in it and the work of taking observations is carried on there. Such a place is called ‘Vedhaśālā’ (or Observatory). It seems probable that in ancient times in our country such places might have been built under royal patronage and reserved for this purpose ; but we do not anywhere find their description. In some places, stone slabs are found on which lines showing directions are marked. It has been mentioned before, that Cintāmaṇi Dikṣit had such an arrangement for showing directions made at his place of residence in Sātārā. In 1884, the author had gone to Indore for taking part in the Sāyana pañcāṅga controversy. There he learnt that a place had been purposely set apart in the palace area, where lines showing directions have been marked, and astronomers, engaged by the Mahārājā Tukoji Rao, sometimes used to take observations there. The author met an astronomer from Bid who told him that some years ago some instruments had been constructed for the purpose of carrying on the work of taking continuous observations with the help of a party of astronomers maintained by the Moghul Government at Hyderabad ; but the work was later on discontinued. The author has seen astronomers at times taking observations by means of tube instruments.

v2.c12.s5.71.2

Such attempts on a moderate scale must have always been made in the past, but we have at present a reliable information about only one attempt of this kind made on a very big scale. It is as follows :—Jaya Simha (page 169) built five observatories. The author is giving below, an extract** from the introduction to his own works KSIZ MOHOMED by name. It will give a complete idia about his efforts :— “so incapable are human beings of comprehending the powers of the Almighty that Hipparchus can be said to be simply a rustic, and Ptolemy only a swallow. The theorems of Euclid are but an imperfect form of divine work. Similar by, thousands of people like Jamsedkasī and Nasīrtusī, have laboured in vain and became fatigued. The calculations made from works on astronomy like those of Sayad Gurganī and Khayānī, the Ākbarśāhi work of Inśil-al-Mulācand and astronomical works of Hindu writers as also those of European writers, do not agree with observed phenomena ; especially, the new moon’s appearance, risings and settings of planets, eclipses and conjunctions of planets do not agree with observation at all. When this fact was told to Emperor Mohomadsāh†, he asked him (i.e. Jaya Simha) to decide the matter. He erected at Delhi instruments like those erected by Mirzā Ulugbeg at Samar-kand . . . . .

v2.c12.s5.71.3

Jaya Simha found that his ideas about the correctness of results could not be realized by brass instruments, because the instruments were small, not convenient for showing minutes of arc, their axes shift their places and get worn out ; the centres of circular plates also shift their places and the planes of instruments get twisted. He thought these to be the reasons why the calculations of Hipparchus and Ptolemy did not tally with observed results. He, therefore, erected the Jaya Prakāś, the Rāma, and the Samrāt instruments which were perfectly stable and built in mortar and stone, whose semi-diameters were 18 cubits, and one grain (yava) in the circumference of which would represent 1 minute of arc. These were constructed and erected with due consideration of geometrical theory, the meridian, and latitude of the place and with careful measurements. They were so designed that it wold be possible to repair the defects caused by the sinking of circular planes, wearing out of axes, shifing of the central points, and irregular spacing of minute divisions. An observatory of this type was built at Delhi. Corrections to be applied to mean motions of planets, which never agreed with observation, were finally determined on the basis of observations taken with these instruments. In order to test the correctness of results of observations taken at the Delhi observatory, he erected similar observatories at Sawai, Jaipur, Mathura, Vāranasī and Ujjayinī.

v2.c12.s5.71.4

Observations taken at all these places tallied with one another. After seven years were spent in taking these observations, it was learnt that similar work was being done in Europe also. Hence, MANUEL, the priest and some other scholars were sent there and the planetary tables compiled 30 years ago and published in the name of LIEL*, were brought through them. The calculations made from them, however, did not agree with observations; it was found that there was an error of about 1/2 degree and some perceptible etror in the case of other planets. Hence, under the direction of the Emperor, a work was compiled containing formulae and mathematical processes for calculation, which were very precise and correct. Its calculation exactly tallies with observation. (The emperor’s name was given to the work as a mark of honour.)”

v2.c12.s5.72

∗ While this chapter was being printed (during the months of Vaiśākha and Jyestha of Śaka 1818) Mr. Naraso Gaṇeśa Bhānu, a resident of Mirāj, sent to the author some papers on which he had copied out diagrams of some of the instruments. Bhānu is not an astronomer. He is at present a pensioner of the Mirāj State, still, he has a great liking for this subject. The original instruments of which these were the copies were constructed by one Sakhārāma Jośī, a resident of Koḍoli near Kolhapur, between Śaka 1712 and 1718. Of these, some were probably made of cast brass, as stated by Bhānu. They include grades of some instruments and ‘turya yantra’, ‘phalak yantra’ ‘dhruvabhramana yantra’ and other instruments. One kind of Yantrarāj instrument was constructed at Saptarṣi (Sātārā) in Śaka 1712 ; it has marked on its dial 17° 42′ as the latitude of Sātārā, and the altitudes of junction stars of 27 asterisms and of some other stars at the times of transit, along with their directions ; e.g. the altitude of Maghā has been given as 83° 57′ South. Another Yantrarāj has been constructed for Karavīr (or Koḍoli) in Śaka 1718. It has marked on it 17° 21′ as the latitude of Karavīr (Koḍoli) and the altitude of Maghā as 84° 15′ South. According to modern astronomy, the latitude of Sātārā is 17° 41′ and that of Kolhapur 16° 41′, and in Śaka 1718, the declination of the junction star of Maghā was about 12° North ; and the transit altitudes of the star were 84° 19′ at Sātārā and 85° 19′ at Kolhapur. Anyway, Sakhārāma Jośī appears to have been very painstaking. The above-mentioned instruments are at present with his great grandson Sakhārāma Śāstri at Kadeguddi near Belgaum in the Śāhapur Taluka. His another great grandson Moraśāstri lives at Mirāj, and he has also some instruments with him.

v2.c12.s5.73

∗∗ This extract has been taken from an article by the well known scholar, William Hunter, published in Asiatic Researches, Vol. V, pp. 177-211.

v2.c12.s5.74

† He was on the throne at Delhi from 1720 to 1748 A. D.

v2.c12.s5.75

HUNTER, visited four out of the five observatories about the year 1799 A. D. and wrote their description in the “Asiatic Researches” mentioned above. It is not given in full for want of space. The description of the observatory at Vāranasī, as given by Sherring (1868 A. D.) in his English book on the city of Vārānasī, is given here, the description* being based on an article by Paṇḍit Bāpūdeva on “Instruments located in the Māna Mandira”, (Other observatories are constructed on the same plan.):--This observatory is situated on the bank of the Ganges at a spot known as Māna Mandira† Ghat. It is known as ‘Māna Mandira’. This building and the whole locality is at present in the possession of the Mahārājā of Jaipur. The observatory building is quite firm and strong. After ascending the steps on the outside, one enters into the square. After crossing it through, one reaches a staircase which leads to the main part of the observatory. Some of the instruments in the observatory are very huge in size. This structure is likely to last for thousands for years very easily. Still, they are so delicate that they could give very accurate results as desired by the original constructor of these instruments. A Brāhmaṇa is appointed to look after its upkeep; but it has not been maintained by him in a good condition. The instruments are getting damaged on account of heat and rain; and their parts and subdivisions, being worn out, are vanishing away. After entering the observatory, one sees the ‘wall instrument’ (Bhitti Yantra). It is a wall 11 ft. high and 9 ft. 1½" long, built in south-to-north direction. With the help of this instrument, the altitudes and zenith distances of the noonday sun, its maximum declination and the latitude of the place can be found. There are two large circular structures near, one is made in stone and the other in mortar; and there is also a square structure made of stone. This might have been used for finding the shadow of the gnomon and the azimuth. But all the marks on them are now obliterated. There is a very big instrument known as Yantra Samrāt (the emperor of instruments). This is another wall 36 ft. long and 4½ ft. thick and build in the south-north direction. One end of the wall is 6 ft. 4½" high and the other is 22 ft. 3½" high; and this wall is gradually elevated towards the north so that the pole star is visible in the plane. With the help of this instrument, the meridian distance, declination and right ascension of celestial bodies can be found. There is another double wall instrument here. To its east is erected a Nāḍi Valaya instrument made of stone. There is similarly another small model of the Yantra Samrāt instrument. Near to it is a Cakra-Yantra fitted between two walls. It was used for finding the declinations of stars; but at present it is nor in good condition. There is a huge Digamśa instrument near it. It was used for finding the azimuths of stars. It consists of a pillar 4 ft. 2" high and 3 ft. 7½" wide. There is another concentric wall having double its height and build at a distance of 7 ft. 3½" from it. The top surfaces of both the walls are graduated in 360° and directions are noted on them; there is another Nāḍivalaya instrument to its south, but the marks on it are obliterated.

First 86 of 94 passages. Read on

Linked texts (16)