Anand M. Sharan


Faculty of Engineering

Memorial University

St. John’s, Newfoundland, Canada A1B 3X5

E-Mail :


Date : March 2, 2006



            In this work, the events of the declining years  of Moghul Empire are studied. In these years, Sawai Jai Singh played a very important role,  which is not very commonly understood by the scientific community. He kept his scientific interest alive even when he was fighting numerous battles, and built his solar observatories. Based on his observations, he published an accurate astronomical table called ‘ Zij-i- Muhammad Shahi ’. The actual construction times of these observatories are established from the historical study.


            There exists a lot of confusion about the construction times of the five observatories built by Sawai Jai Singh. The times range from 1719 to 17373.  The most common belief is that the Delhi observatory was the first observatory built and then followed by other four.  The purpose of other observatories was to assist in improving the tables for astronomical observations such as auspicious times, new moons, eclipses etc1.

            The author of this paper got interested in the life of Sawai Jay Singh because the author himself has worked in the field of solar energy and utilized this energy1,2. The instrument built for this purpose can be called as Surya - Mukhi Yantra ( Sun Facing Instrument ) where optimal ( minimal ) energy is needed to reliably track the sun based on the two motions ( spin and orbital ) of the earth. This instrument is an improvement over other photo – sensor based instruments.

            The objective of this research is to show, based on historical facts available, that it was not the case.  The actual truth is known from the study of Sawai Jay Singh’s life. From this study, one can wonder at the genius of Sawai Jai Singh as to how he could be so brave in battles that he had to fight in the most difficult times of the Indian History, and yet carry out his research interests unparallel in human history. No other scientist has achieved these goals.



            Sawai Jai Singh was born in the year 16884,5. He  did  his early education at Benaras ( called  Varanasi these days  )  as was his family tradition. His great grandfather, Mirza Jai Singh, had also sent his two sons to Benaras.  Sawai Jai Singh had shown early interest in learning mathematics and astronomy, widely recognized as two allied fields since the ancient times in India.

            He succeeded his father to the throne in the year 1700 at age of 12 due to the untimely death of his father. Aurangzeb was the ruler at Delhi  at that time and was fighting with the Marathas in south India. Sawai Jai Singh was sent to Deccan in the year 1701 under Bidar Bakht, son of  Prince Azam who was the second of the three sons of Aurangzeb5. Sawai Jai Singh showed exemplary bravery during Moghul’s  win over the Khelna fort from the Marathas.

            Prince Bidar Bakht was very pleased with Sawai Jai Singh and he was sent to Khandesh with a promotion . In December 1704, Prince Bidar Bakht, himself a governor,  appointed Sawai Jai Singh as the deputy governor of  Malwa but the Emperor, Aurangzeb,  did not approve of this appointment5,6 He, Sawai Jai Singh through his attorney,  tried to make petitions for the deputy governorship in the Court and finally succeeded in December 1705. We will see later that Ujjain, which is in Western Malwa, was the astronomical center for the Hindu Astronomy7.8. It is also reported that he met a Maharashtrian Brahmin, Jagannath in Deccan and this person was well versed in astronomy, and later on – translated several works from Arabic and Persian into Sanskrit4. He, Sawai Jai Singh,  fought against the Marathas in Gujarat until 1707 along with Bidar Bakht.

            Aurangzeb died in 1707 and the battle of succession began. Prince Muazzam, the eldest prince,  won this battle  fought near Agra, where Sawai Jai Singh fought along Prince Azam first and then switched sides after seeing that winning the battle along with Prince Azam was impossible. Prince Muazzam ascended the throne as Bahadurshah. Bahadurshah did not like Sawai Jai Singh’s switching sides which other Rajput kings had also done5. Later on, these differences were reconciled. Sawai Jai Singh had moved to Rajasthan and lived there at Amber.

            Table 1 shows various Moghul kings who ruled from Delhi. The political situation was very fluid at that time. There were lot of uncertainties. No one could rule for longer period of time due to the interference of two brothers called Saiyid Brothers, who made and deposed the rulers at their whim.  In the year 17136, Farrukhsiyar ascended the throne at Delhi. He appointed Sawai Jai Singh as the viceroy of Malwa in October, 1713 to keep Malwa from falling into the hands of Marathas. He arrived at Ujjain in February, 1714. There, he was also facing problems from Afghan soldiers. At Malwa, he performed excellent service to the Moghul ruler and kept the Marathas and Afghans in check. But, from 1715 to 1717, he was called by the Emperor for various other duties away from Malwa because the Emperor was facing problems from Saiyid Brothers at Delhi and Jats near Agra. His father had also fought against Jats , and Sawai Jai Singh had gone along with his father in those battles. In  November, 1717, he finished with Malwa and was replaced by Mohammad Amin Khan.

            Sawai Jai Singh went to fight against Churaman Jat near Agra. During the fight, Sawai Jai Singh was having problems with Saiyid Abdullah, the wazir who finally arranged the surrender of the Jat in 1718 , and Sawai Jai Singh could not get the credit for it.

            In the mean time, the rulers were changed three times in 1719 by Saiyid Brothers, and when, finally, Mohammad Shah became the ruler ( see Table 1 ) and he arranged for the murder of these two brothers after ascending to the throne. The second brother was murdered in 1722.

            In August 1722, Sawai Jai Singh was appointed subahdar ( viceroy ) of Agra and Mohammad Shah was the ruler at Delhi and ordered Sawai Jai Singh  to capture Thun, the capital of Jats who had rebelled again against the ruler at Delhi. Sawai Jai Singh successfully did the job of defeating the Jats.

             Only after the elimination of Saiyid Brothers, and defeating of the  Jats, could Sawai Jai Singh breathe relief in 1722. In the next seven years  from 1722 until 1729, Sawai Jai Singh spent his time in his own pursuits building his capital at Jaipur, and many astronomical observatories at Mathura, Benaras, Delhi, and Jaipur.  He did not go to Malwa until 1729 when he was appointed the viceroy for the second time but for a few months only. Finally, he was appointed again the third time between 1732 to 1737.

            After 1737 when he was relieved of his job at Malwa, he came back to his capital Jaipur, where he spent his remaining years of life until 1743,  when he died.



            The construction times of these four ( Mathura, Benaras, Delhi, and Jaipur ) observatories can be known from the discussions in the next few paragraphs. In 1719 when Sawai Jai Singh  had come back to Agra from Malwa,  he was a part of  discussions in the court of Moghul emperor Mohammad Shah. The heated debate was about how to make astronomical calculations to determine an auspicious date when the emperor could start a journey ? The  discussions involved about the accuracy of important events such as the appearance of the new moon,  eclipses and auspicious times for the Hindus as well as the Muslims. Then, the  ruler had complimented him (Sawai Jai Singh )  for  his knowledge of astronomy,  as is evidenced from a paragraphs of ‘ Zij-i- Muhammad Shahi ’ which,   Sawai Jai Singh had dedicated in the name of the ruler in the year 1728. There are slight variations in this date amongst many historians. The dates  vary between 1727 to 17313. In general, they accept 1728 as the date

            The following are the paragraphs which are given  in3 , and are from Zig-i- Muhammad Shahi ( this translation is based on Hunter ) :


            “He (Jai Singh) found that the calculation of the places of the stars as obtained from the tables in common use, such as the new tables of Saiyid Gurgăni and Khăqăni and the Tas ‘hilat-i Mulla Chand Akbar Shahi, and the Hindu books, and the European tables, in very many cases, give them widely different results than those determined by observation; [the problem was] especially [serious] with the appearance of the new moon—the computations of which did not agree with the observation. “


            “Realizing that important affairs, both regarding religion and the administration of empire, depend upon these; and that in the time of the rising and setting of the planets, and the seasons of eclipses of the sun and moon, many considerable disagreements, of a similar nature, were being found; he represented it to his majesty of dignity and power, the sun of the firmament of felicity and dominion, the splendor of the forehead of imperial magnificence, the unrivalled pearl of the sea of sovereignty, the comparably brightest star of the heaven of empire, whose standard is the Sun whose retinue the Moon; whose lance is Mars and his pen like Mercury; with attendants like Venus; whose threshold is the sky, whose signet is Jupiter; whose sentinel Saturn; the Emperor descended from a long race of kings; an Alexander in dignity; the shadow of God the victorious king Muhammad Shah, may he ever triumph in battle.”


            “He (Muhammad Shah) was pleased to reply, since you, who are learned in the mysteries of science and have a perfect knowledge of this matter, having assembled the astronomers and geometricians [of different schools of astronomy such as those] of the faith of Islam, the Brahmins and Pundits, astronomers from Europe, and having prepared all the apparatus of an observatory, do you so labor for the ascertaining of the point in question that the disagreement between the calculated times of those phenomena and the times in which they are observed to happen may be rectified. “


            “Although this was a mighty task, which during a long period of time none of the powerful rajas had prosecuted; nor among the tribes of Islam since the time of the martyr prince, Mirzä Ulugh Beg, whose sins are forgiven, to the present, which comprehends a period of more than three hundred years, had any one of the kings possessed of power and dignity, turned his attention to this object; yet to accomplish the exalted command received, he undertook the task with a great determination and constructed here (at Delhi) several of the instruments of an observatory, according to the books of the Islamic School of astronomy such as the ones erected at Samarkand.”

            In order to remove these errors - new sets of observations were necessary. Thus,  with the view of setting the astronomical tables straight, Sawai Jai Singh approached the then Moghul emperor Muhammad Shah with the request for permission to build these observatories.

            A brief introduction about Ulugh Beg ( 1393 to 1449 ) 8 , the grand son of Timurlane , and  who was assassinated by his son in 1449,  is in order here because Sawai Jai Singh gave up the brass instruments in favor of large size brick and masonry instruments to achieve the needed accuracy where he could improve upon the existing tables.

            Among the instruments specially constructed for the Ulugh Beg’s  observatory was a quadrant so large that part of the ground had to be removed to allow it to fit in the observatory. There was also a marble sextant. Ulugh Beg's accurate tables of sines and tangents were  correct to eight decimal places. Ulugh Beg's  ‘ Catalogue of the stars’ ,  were the first comprehensive stellar catalogue since that of Ptolemy.

            A very important question arises at this point in time –How could have the ruler complimented Sawai Jai Singh about his knowledge of astronomy, and how could Sawai Jai Singh in 1719 - promise the ruler to improve upon the existing tables made by Ulugh Beg using large brick structure at  Samarkand in Uzbekistan ?

            The author of this paper believes that the answer lies in the fact that Sawai Jai Singh had already built his brick instrument at Ujjain with the help of Hindu astronomers. Ujjain was the center of Hindu astronomy. In addition, the scientific  background that we find in Sawai Jai Singh was an old Hindu tradition were mathematics and astronomy were allied fields.  The evidence of this can be seen in the next few paragraphs.

            Aryabhata (476 – 550 ) was the author of the first of the later siddhantas ( principles ) called Aryabhatiya which sketches his mathematical, planetary, and cosmic theories. This book is divided into four chapters: (i) the astronomical constants and the sine table, (ii) mathematics required for computations, (iii) division of time and rules for computing the longitudes of planets using eccentrics and epicycles, (iv) the armillary sphere, rules relating to problems of trigonometry and the computation of eclipses. He lived at Kusumpur ( modern Patna )  in the state of Bihar ( Magadha ).

            Brahmagupta (598-668) was the head of the astronomical observatory at Ujjain and during his tenure there, he  wrote a text on astronomy - the Brahmasphutasiddhanta in 628. He also developed methods for calculations of the motions and places of various planets, their rising and setting, conjunctions, and the calculation of eclipses of the Sun and the Moon.

            Bhaskara (1114-1185) was the head of the astronomical observatory at Ujjain, continuing the mathematical tradition of Brahmagupta. He wrote the Siddhantasiromani which consists of two parts: Goladhyaya (sphere) and Grahaganita (mathematics of the planets). He also calculated the time taken for the Earth to orbit the sun to 9 decimal places.

           The center of astronomy was originally at Pataliputra in Magadh then moved to Ujjain during the Gupta period, and finally - to Kerala after the Muslims came to north India9.

            The above two paragraphs on Brahmagupta, and Bhaskara show that Ujjain was the center of astronomy since ancient times. The author believes that some form of an observatory remained there at the time of  Sawai Jai Singh, and so did the knowledge of astronomy among the pundits and astronomers. Since, Sawai Jai Singh had his own interest in these subjects as evidenced by the interest he had shown at Benaras, a holy place for the Hindus many of whom believe in Jyotish Shashtra ( Astrology ), he made the best use of his governor’s ( subahdar’s ) position at Ujjain.

            The author believes that it  was the Samrat Yantra ( see Fig. 1 ) built at Ujjain in the years before 1717 , was the proto-type ( smaller unit  )  of the subsequent Yantras to be built at Delhi in 1724, and Jaipur in 1728. As time progressed, he built improved versions at  Delhi and Jaipur and was assisted by the grants from the ruler. He published the astronomical work he completed in 1728 as ‘Zij-e-Muhammad-Shahi (Muhammad Shah’s astronomical tables). Therefore, one can say that Sawai Jai Singh was satisfied and confident before 1728 to have published his table called ‘Zij-e-Muhammad-Shahi ‘.          The Archaeological Survey of India have sign at Ujjain which shows that it was built in 1719. Sharma4 , in his book has expressed doubts about this date of 1719 but, by going over Sawai Jai Singh’s life above, one can clearly see that it was built before 1719.

            Another reason for this can be seen from Sharma’s book ( page 212, bottom paragraph ), where he writes – “  There are reasons to believe that Ujjain observatory must have been built before 1730. Jagannath, Sawai Jai Singh’s   brahmin astronomer , mentions about this observatory in his book called Samrat Siddhanta written in the year about 1730. “ .

            Sawai Jai Singh left Ujjain in 1717 and returned to Ujjain very briefly for a few months  in 1729 but for several years in 1732. On the other hand , ‘Zij-e-Muhammad-Shahi ‘ was completed in 1728.

            Sawai Jai Singh came to Agra in the year 1717 to deal with the Jat Churaman. He could get over the Jat problem in the year 1722 and then he built other observatories. The one ( Samrat Yantra )  in Benaras is of the same size as that of Ujjain10 ,  and is smaller than those of Delhi, and Jaipur.  The one at Benaras was  built after 1722 but it could be built quickly of the same size as that of Ujjain.

            In other words, the observatories at Ujjain was built first after several trials and errors with the help of Hindu astronomers like Jagannath. There are  numerous literature available in public domain which show that Sawai Jai Singh wanted to build larger instruments made of brass but gave up on such ideas because of the technological limitations of fabrication of  sufficiently accurate instruments. He had to revert back to Ulugh Beg’s idea of building larger instruments made of brick and masonry.

            Jai Singh improved concept of time measurement over Ulugh Beg by building equatorial gnomon which can measure time at a constant rate of the spin of the earth and simpler than an ordinary sundial which is like the Sanku Yantra shown in Fig. 2.  One can note that the tip of the shadow of  the bar is almost along the straight line in the  east – west direction. This is because Ujjain is almost at the Tropic of Cancer. The curves that are drawn on the horizontal plane indicate the locus of the tip of the bar on days - before and after the equinox. The curvature of these curves becomes opposite after the equinox.

            The whole idea of achieving better accuracy was to make observations from several locations. In view of the above, one can correctly conclude that the Ujjain observatory was built  before 1717 when Sawai Jai Singh had spent considerable number of years, and  experimented with his masonry instrument at Ujjain before undertaking the task in the Moghul Court of correction of  the existing tables of Ulugh Beg. This experimentation at Ujjain would have given confidence to Sawai Jai Singh to promise the ruler in his Court about improved accuracy,  otherwise, it would have been foolish on the part of Jai Singh to openly declare in the Court about his plans to improve the tables.

            Secondly, as the quoted paragraphs from the ‘Zij-e-Muhammad-Shahi ‘ already point out that -  In the year 1719, the ruler was very much impressed by the knowledge of Sawai Jai Singh.


            Where is the evidence, without building any of the observatories,  to show that indeed,   Sawai Jai Singh had acquired the mastery in astronomy ?

            As far as Malwa is concerned, he was again appointed subahdar in October,  1729 but this appointment lasted for 10 months only due to the interference of  Muhammad Khan Bangash6. But, again, Sawai Jai Singh was made the subahdar in September, 1732 until August, 1737.

            In all these observatories, a horizontal surface is essential. Before constructing their masonry instruments, Jai Singh and his associates selected a suitable ground first and leveled it with water standing in masonry channels built just for this purpose. Such masonry channels may still be seen at Jaipur and Ujjain.

            The idea behind building a number of observatories at different locations in the northern India was to make the same observations from different places and thus reduce the errors introduced due to the limits of resolution of human vision.  Sawai Jai Singh built the three small ones at Ujjain, Mathura, and Benaras with the help of Hindu astronomers who themselves had limitations in civil engineering ( architectural engineering ). Building larger brick and masonry instruments was beyond their expertise. So, he took the help of Vidyadhar Bhattacharya, a Bengali brahmin architect whose ancestors were settled at Jaipur by Mansingh I.  This  architect used his knowledge of Shilpashashtra  in building the Delhi Jantar Mantar in 1724, and further improved upon his design for the Jaipur observatory. This observatory had a few instruments starting in 1728, and the construction ended in 1735. The building of the city of Jaipur took place  on 18th November, 17276 which included construction of surrounding walls, and gates  when appropriate rituals ( Samkalpa ) were performed.



            Based on this study, the following statements can be concluded:

1.         Sawai Jai Singh’s astronomy was basically a Hindu Astronomy, and he was assisted by     Hindu astronomers at Ujjain to perfect the technique of building his masonry     instruments.

2.         Ujjain was the first observatory built,  not Delhi.

3.         The Ujjain observatory was built around 1717 A.D.

4.         All the other four observatories at Mathura, Benaras, Delhi, and Jaipur  were built before 1728 when ‘ Zig-i- Muhammad Shahi ’  was published.

5.         ‘Zij-e-Muhammad-Shahi ‘  was published after the observations made from all       the five             observatories.



  1. Solar Tracking System - U. S. A. , Patent No. 5,632,832, Issued, May 27, 1997.
  2. Solar Energy Powered Electric Vehicle- U.S. Patent No. 6, 021, 862 Dated Feb. 8, 2000.
  4. Sharma, V.N., “ Sawai Jai Singh and His Astronomy “, Motilal and Banarsidas, 1995, Delhi, pp  1-19 ; 85 – 120 ; 191-233.
  5. Bhatnagar, V. S. , “ Life and Times of Sawai Jai Singh 1688 – 1743 “, Impex India Delhi, 1974, pp 1-197
  6. Sarkar, J., “ A History of Jaipur “, Orient Longman, 1984, Hyderabad, India, pp  156 – 227.
  9. Joseph, G, G., 2000, “The Crest of the Peacock: Non - Europeans Roots of Mathematics “, Princeton, U. S. A , Chs. 8, and 9 .
  10. Kaye, G. R., “ A Guide to the Old Observatories “, The Academic Press, 1985, pp  32 - 56








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