The Jaipur Observatory from atop one of the 12 Rasivalayas
Sawaii Jai Singh was however, aiming for a clearer picture of the entire sky and the systems that governed it, for which his Yantras were eminently suitable.Anisha Shekhar Mukherji, Jantar mantar: Maharajah Sawaii Jai Singh’s Observatory in Delhi.
On the topic of why Jai Singh chose not to use telescopes in his observatories
Jai Singh was born in 1688 at Amber in the region of Rajasthan that is now Jaipur. He ascended the throne when he was 12 years old, following the death of his father, Bishan Singh. The young king was bright, eager to learn, and socially and politically astute. Among his many later accomplishments, he founded the city of Jaipur which bears his name, and was responsible for much of it’s design.
India at this time was under the rule of the Mughals who distributed their power through the leaders of existing dynasties such as the Rajputs, Marathas, Pashtuns, and Sikhs. As a young man, Jai Sing, who came from the royal family of the Kacchawahas, led his troops to support the emperor Aurangzeb who was carrying out a campaign against the Marathas in the Deccan. It was during this campaign, around 1700, that Jai Singh met Pandit Jagannatha Samrat, who became his guru and later his chief advisor in matters of astronomy. At the end of the campaign, Jagannatha accompanied Jai Singh back to Amber, where he expanded his knowledge through the study of Jai Singh’s extensive collection of Islamic texts. As jai Singh’s chief astronomer, Jagannatha was a major influence in the design of the jantar Mantar, and the two men remained lifelong friends.
In the early 1700s, when Jai Singh conceived of his ambitious observatory project, the telescope had been in use by astronomers in Europe for over 100 years. Why then, did this highly educated ruler, who knew of the telescope and it’s applications in European astronomy, choose naked eye observation as the basis for his observatories?
One has to appreciate the culture in which Jai Singh lived. It is a culture that throughout its history has embraced the richness of sensory experience in its arts and sciences - exemplified in the precise and complex forms that developed in art, architecture, and music. Observation of natural phenomena, including the apparent movement of stars and planets became a part of the Hindu’s world view, and informed a myriad of life processes from agricultural practices, to religious rituals, to personal decisions of when and who to marry.
For astrologers, the tables known by the arabic term Zij, which indicated the positions of the stars and planets at any given date and time, were critical to their practice. To create these tables, they used the astrolabe, an ancient instrument that can be used to map the local sky and make a variety of astronomical calculations. Invented by the Greeks in about 150 BC, and further developed by both Islamic and Indian astronomers, the astrolabe is an instrument both practical and beautiful. By the 14th century, Indian astronomers had perfected the instrument and were producing individual models with fine craftsmanship and beautiful ornamentation. Jai Singh would have received his early instruction in astronomy through the use of the astrolabe, and in fact one of the early instruments at his observatory in Jaipur is the Yantraraja, a great Astrolabe approximately 8 feet in height.
In spite of the importance of the astrolabe in astronomical calculations, Jai Singh noted that the tables that had been created earlier were often not in agreement with current observations. His own research suggested that the brass instruments that had been used to establish the earlier tables may have lost accuracy due to the wear of their moving parts. It was in part, in reaction to this problem, and also through his own studies of geometric models, that Jai Singh conceived of an observatory with the stability and permanence of masonry, and the capacity for accuracy arising from large scale.
Modern scholars of Jai Singh and his astronomy suggest there may have been other factors that motivated him. In the political turbulence of his times, it may have suited both his need to maintain good standing with the seat of power in Delhi, and his need to maintain authority in his own region, to erect these monumental structures.
Jai Singh built 5 observatories in west-central India. All but the observatory at Mathura are in existence today