Development of astronomy in India has come a long way since the Vedic times and now ISRO heads our space exploration and research in astronomy.

When comes Indian astronomy, an image that automatically comes to our mind is that of the Jantar Mantar. It was built by Sawai Jai Singh of Jaipur in the 18th century .The collections of huge instruments for astronomical observations were fundamentally based on ancient India’s astronomy texts. Five Jantar Mantars were built to revise the calendars and make a more accurate collection of tables that could predict the motions of the major stars and planets. This data was to be used for more accurate time measurement, improved predictions of eclipses and better tracking of positions of stars and planets with relation to earth. They are so large in scale that it is supposed to have been aimed at increasing their accuracy. In the Jantar Mantar, one can find the world’s largest sundial and literally see the sun’s shadow move every second. Records also show that telescopes were built and used in certain observations. This kind of accuracy helped produce in those ages some remarkably accurate results, which even contemporary Europeans could not beat.

One important lesson to learn from the Jantar Mantars is that the Raja built five of them. He could have built just one and been happy with the results. He built five so that the results given by one observatory could be verified against those of another. This possibility of verification obviously reduced the chance of human error involved when taking readings on an instrument. Also, the five observatories were in five different cities. Thus, one could check the position readings of heavenly bodies from different parts of earth and again verify the overall results. This shows a strong display of the scientific enquiry method in the minds of our past astronomers.

The ideas behind Jantar Mantar came from ancient Indian texts written by Aryabhata, Varahamihira, Bhaskaracharya and others. The most important texts of ancient Indian astronomy had been implied between the 5th and 15th century -the classical era of Indian astronomy. The more familiar ones among these works are Aryabhatiya, Aryabhatasiddhanta, Pancha-siddhantika and Laghubhaskariyam. Ancient Indian astronomers were notable in several respects. Their achievements are even more baffling considering they never used any kind of telescopes. They put forth the sun-centric theory for the solar system, elliptical orbits for planets instead of circular ones, reasonably accurate calculations for the length of a year and the earth’s dimensions, and the idea that our sun was no different from the countless other stars in the night sky.

Somewhere during the Middle Ages, progress in the field of astronomy stood still and an admixture of astronomy and astrology arose. With colonization, the European school of astronomy displaced our own. The last remarkable astronomer in pre-Independence India was Samanta Chandrasekhars. His book Sidhant Darpana and his use of simple instruments in getting accurate observations earned him praise even from the British.

In our present era, the Indian space programme stands on the contributions made by two giants in the field of physics-Homi J Bhabha and Vikram Sarabhai. It was their tireless efforts, which initiated work in space research under the Department of Atomic Energy.

Over this period of time, India also produced some remarkable astronomers and astrophysicists Meghnad Saba and Subrahmanyan Chandrasekhar are two world renowned names in astrophysics.

On the side of the observational astronomy, we had Dr M.K. Vainu Bappu-till date the only Indian to have a comet named after him/her. Currently, the Giant Meter-wave Radio Telescope (GMRT) at Khodad near Pune is the largest of its kind in the world. The Kavalur observatory, named after Dr Bappu, is one of the best equipped in the eastern hemisphere.

Jantar Mantar-Ancient Astronomical Observatories of India and Some Instruments

Historically, Indian astronomy developed as a discipline of Vedanga or one of ‘auxiliary disciplines associated with the study of the Vedas. The oldest known text is the Vedanga Jyotisha, dated between 1400-1200 BC.

Indian astronomy was in its peak in the fifth-sixth centuries with Aryabhata and his Aryabhatiya representing the pinnacle of astronomical knowledge. Later, Indian astronomy influenced Muslim astronomy. Chinese astronomy, European astronomy and others significantly. Other astronom of the classical era, who further elaborated on Aryabhata’s work, include Brahmagupta, Varahamihira and Lalla.

An identifiable astronomical tradition remained active throughout the medieval period and into the eighteenth century, especially within the Kerala school of astronomy and mathematics founded by Sangamagrama Madhava (1350-1425 AD) of Irinjalakkuda in Kerala.

The classical era of Indian astronomy begins in the late Gupta era, in the fifth-sixth centuries.

The Panchasiddhantika (Varahamihira, 505 CE) approximates the method for determination of the meridian direction from any three positions of the shadow using Gnomon or Sanku.

Once, while visiting the court of Emperor Muhammad Shah, Maharaja Jai Singh II of Jaipur overheard a loud argument about how to calculate the most astronomically advantageous date for the purpose of the emperor beginning a journey. To the Maharaja, the debate highlighted the need for education in the field of astronomy and for an observatory that could make accunte astronomical calculations. The idea for the Jantar Mantars or calculation instruments was bom The Jantar Mantar consists of a number of structures in stone, brick and marble, cach of them marked with astronomical scales and designed to serve a specific purpose of the observatories originally built at Delhi, Jaipur, Mathura, Ujjain and Varanasi; all observatories dill exist except the one in Mathura.

Among the devices used for astronomy was Gnomon, known as Sanku, in which the shadow of a vertical rod is applied on a horizontal plane in order to ascertain the cardinal directions, the Latitude of the point of observation and the time of observation. This device finds mention in the works of Varahamihira, Aryabhatta, Bhaskara, Brahmagupta, among others.

The armillary sphere was used for observation in India since early times, and finds mention in the works of Aryabhatta (476 CE). The Goladipika a detailed treatise dealing with globes and the armillary sphere was composed between 1380-1460 CE by Parameswara. Probably, the celestial coordinates of the junction stars of the lunar mansions were determined by the armillary sphere since the seventh century. There was also a celestial globe rotated by flowing water.

The seamless celestial globe invented in Mughal India, especially in Lahore and Kashmir, is considered to be one of the most impressive astronomical instruments and remarkable feats in metallurgy and engineering. All globes, before and after this, were seamed, and in the twentieth century, creating a seamless metal globe was believed by metallurgists to be technically impossible, even with modern technology.