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The Astronomical Observatories of Jai Singh c12: Chapter IX.—Ujjain Observatory

The Astronomical Observatories of Jai Singh c12

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English

Contents

Chapter IX.—Ujjain Observatory

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Latitude . . . . . . . 23° 10′ 18″ N. Longitude . . . . . . . 75° 46′ 2″ E. of Greenwich. Height . . . . . . . 1500 feet. Magnetic Declination . . . . . 0° 45′ E. (1915). Local time is 26 minutes 52 seconds after standard time.

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50. The observatory is situated to the south-west of the present city, in the quarter called Jaisingpura, on the north bank of the river Sipra. From the Water Works it is half a mile west. The general situation is seen in the attached map, and in figure 60. The river bank is corroding away, and about a quarter of a mile to the east of the observatory is seen the remains of a well, now standing in the river itself. The observatory is 125 feet north from the river, and is hardly in danger owing to this proximity; but the drainage about the observatory is not under control. There is a small, and, apparently, fresh nullah quite close by, and the foundations of the Digaṁśa Yantra have already been partly worn away.

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51. The observatory now consists of the following instruments:—
(a) The Samrāṭ Yantra.
(b) The Dakshiṇovṛitti Yantra.
(c) The Nari Valaya Yantra.
(d) The Digaṁśa Yantra.

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These are all in a state of ruin. The foundations of the Digaṁśa Yantra have evidently moved, and its walls are badly cracked. The Dakshiṇovṛitti Yantra is inclined to the perpendicular at an angle of about 5 degrees. This is possibly due to the faulty structure, for the foundations for this heavy mass of masonry seem to be inadequate. The Samrāṭ Yantra is in a dilapidated state, and the styles and graduation have disappeared from the Nari Valaya.

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Of the Samrāṭ Yantra only a skeleton remains. In the general plan (plate XXIV) it is shown as though complete, but figure 61 shows its actual present state. It is, practically, of the same size as the one at Benares, and the smaller one at Jaipur, namely, 22 feet high, the edge of the gnomon 47½ feet, and the radius of each quadrant 9 feet 1 inch. In 1796 or thereabout, when Hunter visited Ujjain, the quadrants were divided into ghaṭis and subdivisions. From the edges of the quadrants, where they intersect the walls of the gnomon, lines at right angles (GH, EF figures 34 and 35) were drawn on the gnomon, and perpendicular to its edge. From the points (H, F), where these lines meet the edge of the gnomon, scales of tangents were marked on the edges. All these graduations have disappeared. (For the theory of the instrument see page 36.)

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The Dakshiṇovṛitti Yantra (‘Meridian instrument’) is shown in plate XXIV and in figure 62. The masonry work is fairly intact, but the graduations have disappeared. The instrument was originally something like that at Jaipur (figure 56). It consists of a wall lying in the meridian, and on its east face was a double quadrant, the centres of which were at points near the top corners of the wall and 25 feet apart. A portion of one quadrant is still visible, engraved in the lime plaster with which the wall is faced, but this is probably not the original graduation. On the ledge below the quadrants there are traces of a scale of tangents. On the west side is a flight of steps (figure 62) leading to a narrow platform at the top. At the south-west end of this platform is a small pillar, 2 feet in diameter: according to Hunter this was "graduated for observing the amplitude of the heavenly bodies at their rising and setting"; and was called Agra Yantra ('amplitude instrument'). The graduations have now disappeared. At the middle of the platform, and on the east side, is a small projection of the parapet, 2 feet 4½ inches long and deep. On this, Hunter tells us, was "constructed a horizontal dial called Puebha Yunter." There is no sign of this dial now.

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Fig. 61 UJJAIN OBSERVATORY. GENERAL VIEW

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Fig. 63 UJJAIN OBSERVATORY. DIGAMBA YANTRA

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Survey of India Offices Calcutta 1913

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Fig. 60 UJJAIN OBSERVATORY. DISTANT VIEW

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Fig. 62 UJJAIN OBSERVATORY. DAKSHINO VRITTI YANTRA

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The Nari Valaya or 'Circular dial' is constructed on the same principle as those at Benares and Jaipur. It is situated a few feet to the south of the Samrāṭ Yantra, and consists of a cylinder 7½ feet long 3 feet 7½ inches in diameter, whose axis is fixed horizontally in the plane of the meridian, the faces of the cylinder being cut parallel to the plane of the equator. In the centre of each face, and at right angles to it, was an iron style, round which was a circle graduated into ghaṭis and subdivisions. The styles and graduations have disappeared.

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The Digamśa Yantra is similar to the one at Benares. It is situated quite close to the Samrāṭ Yantra on the east side and consists of an outer circular wall, 36 feet 10 inches in diameter and 8 feet 10 inches high. Concentric with this is another wall, 24 feet 4 inches in diameter and 4 feet 6 inches high. Originally there was a pillar at the centre, but it has been removed. Cross wires were stretched north to south and east to west on the outer wall. At the four points of the compass, in the outer and inner walls, were arched openings, but all of those in the outer wall, except that to the west, have been filled up. The outer walls are badly cracked, and a great part of the foundations is now exposed. This is due to the bad drainage of the slope to the river. The nullah that passes close by the Digamśa Yantra could easily be diverted. In Hunter's time the building was "roofed with tiles and converted into the abode of a Hindu deity," so that Hunter was unable to examine its construction. This is of interest, as showing that, even in the eighteenth century, the instrument was no longer used for astronomical purposes. Hunter also writes¹:—"Urania fled before the brazen fronted Mars, and the observatory was converted into an arsenal and foundry of cannon."

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¹ There is some ambiguity in Hunter's reference but Fanny Parkes (Wanderings of a Pilgrim, etc., II. 209) turns it into a certainty, for she says: "The observatory at Oujein has since been converted into an arsenal and foundry of cannon." Her information was obtained from Hunter.

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52. There appear to be no records of any astronomical instruments at Ujjain, earlier than those installed by Jai Singh. The date of the construction of his observatory is uncertain, but it was probably between A.D. 1728 and A.D. 1734 (see page 139). There is no record as to whether, or not, the instruments were ever used for actual systematic observation, but we know that, before the end of the eighteenth century, they had ceased to be so used.

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The earliest known description of the Ujjain observatory was by the Jesuit priest, Tieffenthaler, who travelled in India from 1743 to 1786. His account ¹ of the observatory is as follows :—

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¹ *Historische-geographische Beschreibung von Hindustan.* vol. i. 246.

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"Not far from there is a suburb built by Djésing, King of Djépour, a ci-devant governor of this province (Mālwa). An astronomical observatory is to be seen there, with instruments, made of cement : namely two equinoctial dials, one large and one small ; a gnomon (axis mundi) elevated according to the height of the pole at this place, and set in the meridian ; and on either side of this is a quadrant of a geometrical circle ; also a dial made in lime, and a meridian wall in stone."

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The only other account of any value is that by Hunter (from which we have already quoted) who accompanied the Agra Resident's expedition to Ujjain in 1792-93. He briefly describes the instruments, and he states that Jai Singh determined the latitude of Ujjain to be 23° 10' N., and Hunter himself took considerable trouble in verifying this result, which he considered correct to the minute.²

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² *Asiatic Researches* V, 1799, p. 194 f.

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53. Restoration.—There has been considerable discussion as to the best means of preserving Jai Singh's observatory at Ujjain ; and it has been suggested that it should be restored and improved, so as to be of help in the work of reforming the Hindu calendar. The instruments, as they now stand, are, however, far too dilapidated to be restored satisfactorily for practical purposes. They should be preserved as relics, and only restored to such an extent as to show them, more or less, in their original state. To attempt to do more with them would be foolish. Originally the instruments were by no means the best devised by Jai Singh, and they never were instruments of accuracy in the modern sense. The work of restoration should have for its end the proper preservation of the instruments in their original form : and to this end I make the following suggestions :—

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(i) The drainage should be properly regulated. (It should be quite a simple matter to divert the drainage from the foundation of the instruments.) It also may be considered desirable to construct some protection on the river front. (ii) The ground surrounding the instruments should be levelled ; the trees removed, etc. (iii) For the particular instruments the following suggestions are made: (a) The Samrāt Yantra.—This should be restored on the same lines as the Benares instruments, but European graduations and symbols should not be employed. (b) The Dakshiṇovṛitti Yantra presents considerable difficulty because of its list. The only solution seems to be, to take it down and rebuild it stone by stone on a secure foundation. (c) The Digamśa Yantra presents no great difficulty, but parts of the walls will have to be taken down and rebuilt. Its permanent preservation is a matter of drainage. The cross wires should be replaced, and the graduations on the walls remarked. (d) The Nari Valaya requires regraduation and the replacement of the styles.

Ujjain, the Greenwich of India

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54. Ujjain (the οζηνη of the Greeks), or Avanti, as it was often called, is mentioned in early Hindu Astronomical works as situated on the prime meridian, and tradition also makes it the centre of astronomical learning in India.

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UJJAIN OBSERVATORY

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ELEVATION ON . A . B

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SECTION ON . E . F

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SECTION ON C . D.

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GENERAL PLAN.

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Latitude 23° 10' N Longitude 75° 47' E

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0 5 10 20 30 40 FEET

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In the *Pañchasiddhāntikā* (xiii, 17) we read: “Ujjayinī is near to Laṅkā, being situated to the north on the same meridian: hence the noon of the two places occurs at the same time, but their days are unequal with the exception of the equinoctial days.” The latitude is given (v. 19) as 24° N. and “the nāḍikās, arising from the difference in longitude from Yavana, are seven and a third in Avantī, nine in Vārāṇasī.” (iii, 13.)

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The *Sūrya Siddhānta* (i, 62) says: “Situated upon the line which passes through the haunt of the demons,² and the mountain which is the seat of the Gods,³ are Rohītaka and Avantī, as also the adjacent lake.”

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² Laṅkā.

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³ Mount Meru.

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Albīrūnī’s discussion of the position of Ujjain is of considerable interest. He writes⁴: “All canons of the Hindus agree in this that the line connecting Laṅkā with Meru divides the οἰκουμένη lengthwise in two halves, and that it passes through the city of Ujain, the fortress of Rohītaka, the river Yamunā,⁵ the plain of Tāneshar, and the Cold mountains. The longitudes of the places are measured by their distance from this line. On this head I know of no difference, except the following passage in the book of Āryabhaṭa of Kusumapura:—‘People say that Kurukshetra, *i.e.*, the plain of Tāneshar, lies on the line which connects Laṅkā with Meru, and passes through Ujjain. So they report on the authority of Pulīśa.⁶ But he was much too intelligent not to have known the subject better. The times of eclipses prove that statement to be erroneous, and Pṛithusvāmin maintains that the difference between the longitudes of Kurukshetra and Ujjain is 120 yojanas.’ These are the words of Āryabhaṭa. Ya‘ḳūb Ibn Ṭārik⁷ says in his book, entitled the Composition of the Spheres, that the latitude of Ujjain is 4⅓ degrees, but he does not say whether it lies in the north or south. Besides he states it, on the authority of the book *Al-Arkand*, to be 4⅓ degrees.⁸ We, however, found a totally different latitude of Ujain in the same book in a calculation relating to the distance between Ujain and Almanṣūra,⁹ which the author calls Brahmanavāṭa, *i.e.*, Bamhanwā, viz., latitude of Ujain, 22° 49′; latitude of Almanṣūra, 24° 1′. According to the same book, the straight shadow in Lohāniyye,¹⁰ *i.e.*, Loharāni, is 5⅝ digits. On the other hand, however, all the canons of the Hindus agree in this, that the latitude of Ujain is 24 degrees, and that the sun culminates over it at the time of the summer solstice.”

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¹ Yavana is Alexandria, whose longitude is approximately 29° 51′ E. of Greenwich. Seven and one-third nāḍikās=2 hours 56 minutes=44 degrees, and 9 nāḍikās=54°. These give the longitude of Ujjain and Vārāṇasī (Benares) as 73° 51′ and 83° 51′. Their longitudes are approximately 75° 47′ and 83° 0′ 46″.

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⁴ Alberuni’s India (By E. Sachau) i, 316.

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⁵ At Mathurā according to Albīrūnī (i. 308). Rohītaka, he says, is in the district of Multan. It was deserted in Albīrūnī’s time.

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⁶ Fl. circa A.D. 400.

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⁷ Died A.D. 796, see Suter, p. 4.

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⁸ This must be an equinoctial shadow length, which gives a latitude of tan⁻¹ 4 4/12 (or 4⅓) = 20° 57¼′ roughly. The correct latitude is about 23° 10′, which gives a shadow of 5⅝ digits.

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⁹ This is given on the ‘Jaipur B’ astrolabe, with latitude 27° 40′ North. See p. 127.

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¹⁰ Perhaps the Awyībaṣt of Ptolemy. tan⁻¹ 5⅝/12 = 25° 15′ nearly.

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Again he says (i, 308):—"The city of Ujain, which in the tables of the longitudes of places is mentioned as Uzain, and as situated on the sea, is in reality 100 yojana distant from the sea, etc."

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Bhāskara in his *Siddhānta Śiromaṇi* (Gaṇita, vii, 2) writes:—"The line which, passing above Laṅkā and Ujjayinī and touching the region of Kurukshetra and other places, goes through Meru—that line is by the wise regarded as the central meridian of the earth."

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Bhāskara also mentions Ujjain, in several other connexions, as the place of zero longitude, and he gives its latitude as 'one sixteenth of the whole circumference, north of the equator.' This is equivalent to 22½ degrees north, whereas the latitude of the present city is about 23° 11', that of Jai Singh's observatory being approximately 23° 10' 24". Another value was obtained from the length of the equinoctial shadow, which was given as 5 *daṇḍas* 10 minutes, or 310 minutes. This¹ is the shadow of a gnomon 12 *daṇḍas* or 720 minutes high, and hence the latitude= *tan*⁻¹ 310/720 = 23° 17' 40".

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¹ Guerin, *Astronomie Indien ne*, Paris, 1847, p. 146.

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55. The question of the formation of a new observatory at Ujjain is one of great importance. Ujjain is one of the most ancient astronomical centres in the world, and not only should it have a modern observatory, but it should be the centre of Hindu astronomical teaching. Perhaps, one of the most important practical questions to settle is the position of such an observatory, which is to be the position of zero longitude for Hindu astronomers, and is to accord with the traditional position of zero longitude. To assist in this very important matter the annexed map of Ujjain has, with the assistance of the Resident of Gwalior, the Director-General of Archæology and the Surveyor-General, been produced. The Trigonometrical Survey point on the map is Hill 1678, whose longitude is approximately 75°46'44", and latitude approximately 23° 11' 6" North. It is doubtful whether there ever was a fixed position in ancient Ujjain, which was considered as of zero longitude. Rather vaguely, the old city of Ujjain—to the north of the present city—was meant; or, it is just possible, that Jai Singh considered this point when he located his observatory to the south of the present city, and that the site of Jai Singh's observatory is the traditional place—but this is doubtful. The plan now to follow is to fix upon the position of the new observatory and determine its longitude and latitude independently of tradition. The accompanying map should be of help in obtaining the first approximations for the longitude and latitude of such a position, and it is hoped that it will be of use to the Paṇḍits of Ujjain.

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Fig. 65. THE SAMRAT YANTRA, BENARES.

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Fig. 67. DRAWING OF THE BENARES INSTRUMENTS MADE IN 1773.

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Fig. 64. MANMANDIRA, BENARES.

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Fig. 66. GENERAL VIEW OF THE INSTRUMENTS, BENARES.

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