The Astronomical Observatories of Jai Singh c13: Chapter X.—Benares Observatory
The Astronomical Observatories of Jai Singh c13
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Chapter X.—Benares Observatory
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Latitude . . . . . . . 25° 18' 24·9" N. Longitude . . . . . . . 83° 0' 46·1" E. of Greenwich. Height above sea level . . . . 350 feet. Magnetic declination . . . . E. 0° 45' (1915). Local time . . . . . . 2 minutes 3 seconds before standard time.
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56. The observatory is situated on the roof of the old part of the building known as the Mānmandira, which was built by Mān Singh, a Rājāh of Amber, who flourished at the beginning of the seventeenth century. (He died in A.D. 1614.) This building is on the west bank of the Ganges, near the Maṇi Karṇikā ghāt, and 1¾ miles south-east by south from Queen's College. The proper approach is from the river front, that from the city being through narrow, unsavoury alleys. "Though not very architectural in its general appearance," writes Fergusson,¹ "(it) has on the river face a balconied window, which is a fair and pleasing specimen of his (Mān Singh's) age." (Figure 64).
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¹ A History of Indian and Eastern Architecture, vol. ii, 178.
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On the roof of the Mānmandira, as constructed by Mān Singh, and a little over a century after it was built, Sawāī Jai Singh of Jaipur placed the astronomical instruments that now form the observatory. Some time about the beginning of the nineteenth century the Mānmandira appears to have been enlarged,² and about the middle of the nineteenth century it was restored. In figure 64 the part of the Mānmandira that supports the observatory is to the right: the circular Digamśa Yantra is seen above the three balconied windows.
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² Compare Campbell's drawing (figure 67) and Prinsep's drawing. The latter is given in Benares Illustrated by a series of Drawings, by James Prinsep.
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The general plan of the roof of this part of the building (plate XXVI) shows—
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The larger Samrāṭ yantra (AA), the Narivalaya yantra, the Chakra yantra (CC), the Digamśa yantra (DD), and the smaller Samrāṭ yantra.
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On the east wall of AA is a double quadrant or Dakṣiṇovṛtti yantra, and to the south of AA is another Dakṣiṇovṛtti yantra, not shown in the plan. The grooves shown in the plan were possibly used for levelling purposes.
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57. The Samrāṭ Yantra (AA) is of the same type as those at the other observatories, and is the same size as that at Ujjain and the smaller one at Jaipur. Its height is 22 feet 3¼ inches, the edge of the gnomon is 39 feet 8½ inches long, and the radius of each quadrant is 9 feet 1¼ inches (see p. 36). The edges of the gnomon and the quadrants are faced with sand-stone, and the graduations are carefully marked. On the quadrants every half-hour is marked by two inlaid metal discs, the one towards the north edge being inscribed in Indian characters, while the one on the south is in European figures. Each edge is also graduated into minutes and quarter minutes; and also into degrees and tenths of a degree. The edges of the gnomon are graduated with the usual tangent scales (see page 36). A comparison between a drawing made about 140 years ago (figure 67) and a recent photograph (figure 66) shows that very little alteration has been made, the only noticeable being the inlaid metal discs already referred to, the employment of European symbols and the division into hours instead of ghaṭis.
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On the east wall of the gnomon are two graduated quadrants (figure 66), used as a Dakṣiṇovṛitti Yantra or meridian instrument. Each quadrant has a radius of 10 feet 7 inches. The shadow of one of the pins (fixed at the top of each quadrant) gives the zenith distance at noon, and zenith distances of other heavenly bodies could be observed directly, by moving the eye along the appropriate quadrants. Under these quadrants is a platform (shown in the plan) for the observer. Apparently, in 1773, these quadrants were not in existence (see figure 67), but according to Paṇḍit Bapu Deva Śāstri they were there in 1865.
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The other Dakṣiṇovṛitti Yantra is a self-contained instrument, consisting of a wall lying in the meridian, on the east face of which are two quadrants, each of 7 feet 9½ inches radius. Sir Robert Barker in 1777 stated that the quadrants were of different radii, the larger of which he judged to be 20 feet. If his description be correct, the instrument must have been entirely rebuilt later on, possibly when the Mānmandira was added to. In 1865, to the east of this instrument were three circles of 10 feet 3 inches, 2 feet 4 inches, and 3 feet 5 inches, respectively, in diameter; and also a stone square with sides 2 feet 2 inches. The circles were possibly used for construction purposes.
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The smaller Samrāṭ Yantra calls for little remark. It is 8 feet 3 inches high, and the radius of the quadrants is 3 feet 2 inches (figure 65). If the early drawing (figure 67) is correct, the instrument has been moved from its original position.
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The Nari Valaya (‘circular dial’), or Uttara dakṣiṇo Gola (north and south dial), is a cylindrical dial—the axis of the cylinder pointing north and south, and the northern and southern faces being parallel to the plane of the equator. At the centre of each face, and at right angles to it, is a short iron style surrounded by two circles—the outer one (on the northern face)¹ graduated in hours, etc., and the inner one in ghaṭis, etc. Besides serving as an ordinary dial the instrument marks the equinoxes, since the northern face can only be used for sun observations when the sun is north of the equator. The inscription on the instrument reads:—“Narivalaya Dakshin and Uttra Gola. The use of this instrument is to find whether the heavenly bodies are in the northern or southern hemisphere. It gives time also.”
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¹ There is some indication that this instrument was originally made for northern observations only. See p. 39
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The Digamśa Yantra (‘Azimuth instrument’), marked DD in the plan, is the large circular building at the east of the terrace. It is partly visible in the general view of the Mānmandira (figure 64). The exterior diameter is 31¼ feet, the outer wall is 8 feet 4 inches high and the inner wall and central pillar are each 4 feet 2 inches high, and an iron rod fixed to the central pillar is of the same height as the outer wall. The tops of both walls were originally graduated into degrees, etc.; and cross wires were stretched north to south and east to west on the outer wall. The use of the instrument is to measure azimuths
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GENERAL PLAN.
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ELEVATION ON A. A.
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SAMRAT YANTRA 10 0 10 FEET
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SECTION ON C. C.
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CHAKRA YANTRA 4 3 2 1 0 4 FEET
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SECTION ON D. D.
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DIGAMSA YANTRA 10 5 0 10 FEET
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or horizontal angles (see page 38), but it is now of little practical use, owing to its being surrounded on all sides but one by buildings.
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To the south-east of the Digamśa Yantra there used to be another dial, whose diameter was 6 feet 2 inches. It was on a platform slightly higher than the terrace, and approached by steps. At the present time there is no space to accommodate such an instrument, and Campbell's drawing of 1773 (figure 67) shows no such instrument. However, Williams mentioned that it had been excluded from Campbell's drawings,¹ and it was mentioned by Hunter in 1797 and by Paṇḍit Bapu Deva Śāstri in 1865.
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¹ Phil. Trans. Royal Soc. 1793 i. 45.
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The Chakra Yantra is shown in the plan at CC. It is an equatorial, and was common to most mediaeval observatories. It consists of an iron circle (declination circle) 3 feet 7 inches in diameter, one inch thick and two broad, faced with brass, on which degrees and minutes are marked. The circle is fixed so that it can revolve round an axis parallel to the earth's axis. At the southern extremity of this axis, and on the pillar which supports the instrument, is a graduated circle (hour circle) in the plane of the equator (figure 65). There is no pointer for this hour circle, and according to Hunter there was none in 1797. Attached to the centre of the declination circle is a sighter, consisting of a hollow brass tube (figure 68), but this is comparatively new. Hunter wrote: "Observations with this instrument cannot have admitted of much accuracy, as the index is not furnished with sights; and the pin by which it is fixed to the centre of the circle is so prominent, that the eye cannot look along the index itself." In figure 68 can be seen what is probably the old index and also the new tube sighter.
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The sighting arrangement is fixed to the big circle by a pin, and this pin is fixed by a cotter or wedge, shaped roughly into some semblance of a horse's head (figure 68). In the section on the astrolabe (page 18) it was stated that the Arabs called such a wedge *faras* (' horse '), and that in mediaeval Europe it was generally made into some semblance of a horse's head (see figures 24). "Thorw which Pyn," wrote Chaucer, "ther goth a litel wegge which that is cleped the hors that streyneth alle these parties to hepe." There is abundant evidence to show that the horse shaped design of the wedge was brought to India by the Muslims, and the example on the Chakra Yantra is interesting as evidence of the persistence of a traditional design, and in some degree as evidence of the ultimate source of the design of Jai Singh's instruments.
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FIG. 68. THE FARAS OR HORSE.
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58. History.—The Mānmandira was built about the beginning of the seventeenth century. Campbell's drawing of 1773, and Prinsep's of 1825, and recent photographs enable us, to some extent, to trace the additions and alterations made. The part of the façade that is directly under the observatory belongs to the oldest part of the building, and that part that has no balconied windows is comparatively new (see figure 64). The fine window on the extreme north (right) of the building was given by Prinsep in his illustrations of Benares, and has been described by Fergusson and Havell.
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The astronomical instruments were added by Jai Singh about A.D. 1837.¹ The date is not certain, and nearly every writer gives a different one. Sir Robert Barker, who was almost a contemporary of Jai Singh,² said that the observatory was built by Akbar; Prinsep wrote: "The building was converted into an observatory by Jysing, A.D. 1680" and refers to a supposed description of it by Tavernier³; another writer gives A.D. 1693⁴ and another 1700. Father Boudier who visited Benares in 1734 and made astronomical observations there makes no mention of the observatory. Jai Singh himself tells us that, in order to confirm the observations made at Delhi, he constructed instruments of the same kind at Jaipur, Mathurā, Benares and Ujjain; and the Delhi observatory was probably built about 1724; that at Jaipur was built in 1734, and Williams' date for the observatory at Benares, 1737, may be accepted.
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¹ This is the date given by Williams, who, on all points that can be verified, is extremely reliable. See p. 139.
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² Sir Robert Barker lived from 1729-1789, and went out to India in 1749, six years after Jai Singh's death.
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³ Tavernier died in 1689, three years after Jai Singh's birth.
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⁴ This particular mistake is repeated in the *Encyclopaedia Britannica*, vol. 3, p. 714.
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59. Early Descriptions.—In A.D. 1777⁵ Sir Robert Barker, who was for a short time Commander-in-Chief in Bengal, published a description of the instruments, together with a perspective drawing of the observatory as a whole, and detailed drawings of the Samrāṭ Yantra, done by Lieutenant-Colonel Campbell, Chief Engineer of the Company's service. The perspective drawing is here reproduced (figure 67), and it shows that the main features of the observatory are the same to-day as they were nearly a century and a half ago. There are apparent differences, but some of them may be due to the nature of the drawing: e.g., the Narivalaya and the small Samrāṭ appear to have been displaced slightly; the wall that supports the east quadrant is different in detail; there are no graduated quadrants on the east wall of the gnomon; the edge of the plinth, on which the larger Samrāṭ stands, has changed its alignment; and, in the drawing, no plinth at all is shown for the other instruments. From the notes of Williams and Hunter it appears that the drawing is somewhat incorrect, or, at any rate, misleading for the south-east corner of the terrace, for it shows no trace of the second Nari Valaya, described by them.
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⁵ Sir Robert Barker left India in 1773. His notes and the drawings were probably made in 1872-73.
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Sir Robert Barker's account of the Benares Observatory was of the nature of a communication to the Royal Society, London. Further information seems to have been asked for, and this was supplied by Mr. J. L. Williams of Benares in A.D. 1792, who recorded very careful measurements and added some interesting details as to the history of the place. He writes: "The area, or space comprising the whole of the buildings and instruments, is called in Hindoo, Maun-mundel; the cells and all the lower part of the area, were built many years ago, of which there remains no chronological account, by the Rajah Mansing, for the repose of holy men, and pilgrims, who came to perform their ablutions in the Ganges, on the bank of which the building stands. On the top of this the observatory was built, by the Rajah Jetsing, for observing the stars, and other heavenly bodies; it was begun in 1794¹ Sambat, and it is said was finished in two years. The Rajah died in 1800² Sambat. The design was drawn by Jaggernaut and executed under the direction of Sadashu Ma Makajin; but the head workman was Mahon, the son of Mahon, a pot maker of Jepoor."
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¹ A.D. 1737.
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² A.D. 1743.
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In 1799 Hunter gave a brief description of the observatory, supplementary to the previous accounts. He speaks of the accuracy of Mr. Williams' measurements and explains some of the terms used; and clears up one or two other points. In 1848 Sir Joseph Hooker made excellent drawings of three of the instruments, and in his diary records³ that "the observatory is stil the most interesting object in Benares, although it is now dirty and ruinous, and the great stone instruments are rapidly crumbling away." The only other descriptions it is here necessary to mention are those by Paṇḍit Bapu Deva Śāstri, Lala Chiman Lal, and Paṇḍit Gokal Chand.
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³ Himalayan Journals, 1854, pp. 74-77.
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60. Restorations.—Of previous restorations we know very little. Sherring states that the Brahmans "were utterly careless" about preserving the instruments. According to Havell, the Mānmandira was restored in the middle of the nineteenth century. In 1912 the present Mahārāja of Jaipur ordered the complete restoration of the instruments. This work was very thoroughly done under the direction of the court astronomer, Paṇḍit Gokal Chand.
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The observatory at Benares has long since ceased to be used for practical purposes. The Brahmans consulted by Williams in 1792 all agreed that it "never was used for any nice observations." Its present situation, surrounded on most sides by buildings, is not ideal for astronomical purposes; and the instruments are, of course, very crude compared with those in modern observatories. The value of the observatory is chiefly historical; it is a monument to one of the brightest intellects of India; and it illustrates a very interesting phase of the history of astronomy. It might have another value if advantage were taken, namely an educational one: for the demonstration of the elements of practical astronomy a better set of instruments could hardly be devised. But, apparently, astronomy is no longer studied at Benares, Ujjain and Jaipur.