Indian Astronomy : From Jantar-Mantar to Kavalur
In 1947, the renowned American astronomer Harlow Shapley (1885-1972) lamented that although India produced great astrophysicists like Meghnad Saha (1893-1956) and Subrahmanyan Chandrasekhar (1910-1995), her observing facilities were practically nil.
In that first year of India's independence that remark, indeed, was in order. But during the last five decades the situation has radically changed. Now India possesses several first class facilities for astronomical observations. Now we have a number of radio telescopes in our country, the Giant Metre-wave Radio Telescope (GMRT) at Khodad near Pune being the largest of its kind in the world. At the time of independence India had only two, rather outdated, observatories : one at Kodaikanal and the other at Hyderabad. Now we have new observatories at Nainital, Mount Abu, Udaipur, Japal-Rangapur and Kavalur. The Kavalur observatory, named after its founder Dr Vainu Bappu, is one of the best equipped in the eastern hemisphere, its 2.3 metre aperture telescope being the largest in Asia.
It was after independence that one of our leading astronomers, Dr Manali Kallat Vainu Bappu (1927-82), was first elected Vice-President (1967-73) and then President (1979-82) of the International Astronomical Union (IAU). Also, for the first time in 1985 the IAU Assembly was held in India. All this shows that India has now attained a respectable position in astronomical research. The story of India's endeavours in this field is a fascinating one. But before we come to that it would be useful to have a cursory glance at ancient India's achievements in mathematics and astronomy, as both the subjects were studied together.
Ancient India made some big advances in science because it was in constant contact with other countries. After the conquest of the Indus basin by Darius around 520 B.C. India was thrown wide open to Babylonian influences. Through the Persians, India also came into contact with Greece. These contacts further increased during Alexander's campaign and again when the Greco-Bactrian kingdoms were established in North-West India. All these contacts greatly helped India in enriching her sciences, particularly astronomy.
This long period of intercourse with the west introduced many new ideas in the traditional system of Indian astronomy. The result was the advent of a class of texts called Siddhantas, characterised by a better scientific approach and more comprehensive treatment. There is ample evidence to show that Aryabhata (499 A.D.) and Varahamihira (6th century A.D.) were well-acquainted with Greek astronomy. The most celebrated astronomers after Varahamihira were Brahmagupta (b.598 A.D.), Lalla (8th cent.), Manjula or Munjala (10th cent.), Shripati (c.1039 A.D.) and Bhaskaracharya (b.1114 A.D.). In the post-Bhaskara period not much original work in astronomy and mathematics was done in India till modern times.
By the eighth century the Arabs had extended their conquests from Spain to Central Asia and to the border of India. Under the patronage of the Caliphs books of Indian, Persian and Greek science were translated into Arabic. In about 800 A.D. Aryabhata's treatise Aryabhatiyam was translated into Arabic under the title Zij-al-Arjabhar. Before that, in 772 A.D., Brahmagupta's two works, the Brahmasphuta-Siddhanta and the Khandakhadyaka, were taken to Baghdad and translated into Arabic. The knowledge of Indian numerals and the decimal place-value system reached the Arabs along with the Indian mathematical-astronomical works rendered into Arabic.
The Arab scientists, apart from analysing and commenting on what they inherited, made many original contributions of their own. The Islamic world produced great mathematician-astronomers such as al-Khwarismi (780-850 A.D.), al-Battani (850-929 A.D.), Tabit ibn Qurra (836-901 A.D.), al-Sufi ( 10th cent.), al-Biruni (973-1848 A.D.), Omar Khayyam (c.1048-1124 A.D.) and Nasir al-din at-Tusi (1201-1274 A.D.). The last one was in charge of the observatory at Maragha in Iran. In 1420 A.D., Ulugh Begh, grandson of Timur, built an observatory at Samarkand. Using very big but high-precision instruments he prepared a star catalogue which was much better than that of Ptolemy.
It was with the Islamic rule that Arabic/Persian astronomy came to be introduced in India. The earliest evidence of Arabic/Persian influence on Indian astronomy is of the second half of the fourteenth century. Mahendra Suri, a court astronomer of Firuz Shah Tughlaq (1351-88), composed in 1370 A.D. a treatise entitled Yantraraja. Based on Persian knowledge, it described the construction and use of astrolabe, that wonderful instrument developed to perfection by Arab astronomers. Another Indian astronomer who made use of Arabic/Persian knowledge was Kamalakara (b.1658 A.D.), who wrote a big treatise on astronomy called Siddhanta-Tatva-Viveka.
But it was Sawai Jaya Singh II who showed the greatest interest in Arabic/Persian astronomy. He was born in the ruling family of Amber in Rajasthan in 1686 A.D., one year after Newton published his Principia. He succeeded to the Amber throne at the age of thirteen. Later on he was appointed by Mohammad Shah governor of the province of Agra and then also of Malwa. From an early age Jaya Singh was very much interested in astronomical observations and had acquired thorough knowledge of its principles and rules.
Jaya Singh felt a great urge in reviving the study of astronomy in India. With the aim of preparing new tables, Jaya Singh at first started with the traditional brass instruments. Realising their inadequacy, he discarded them in favour of stone and masonry instruments of huge size. For observing the heavens Jaya Singh built observatories at five places : Delhi, Jaipur, Mathura, Ujjain and Varanasi. The first one was built in Delhi in 1924 A.D. These observatories, which in course of time came to be called 'Jantar Mantar', housed a wide variety of masonry and metal instruments, the most important among them were : Samrata Yantra, Jai Prakash, Rama Yantra, Mishra Yantra and Rashi Valaya. Among the metal instruments used by Jaya Singh the astrolabe was the most significant one.
Jaya Singh, making use of the masonry and metal instruments of his observatories, prepared the astronomical treatise Zij-I -Muhammad Shahi and dedicated it to the reigning monarch Muhammad Shah. The work was completed around 1727-28 A.D. Jaya Singh's court astronomer Pt.Jagannatha, who had mastered Arabic and Persian, translated from Arabic into Sanskrit works titled Rekhaganita and Siddhanta-Samrata. The translation of the former was completed in 1718 A.D. and of the latter in 1731 A.D.
Jaya Singh had established contacts with Jesuit missionaries in India and had also known the telescope. But he did not make use of the Copernican revolution ushered in Europe. He remained a firm follower of the geocentric system of Indian tradition and of Ptolemy. It seems that Jaya Singh had no knowledge of the works of Kepler (1571-1630) or Newton (1642-1727).
In spite of his best efforts for the revival of astronomical studies in India, Jaya Singh remained firmly attached to the medieval tradition. He died in 1743 A.D., exactly two hundred years after Copernicus (1473-1543). Today Jaya Singh's work is only a tradition and his observatories are nothing but archaeological remains.
Modern astronomy arrived in India along with the European merchants and missionaries. At the end of the 17th century the French Jesuit priests of Pondicherry were already using the telescopes. Jesuit priest Fr. Jean Richaud discovered from Pondicherry that the southern bright star a Centauri is in fact a double one.
The merchants of the East India Company also brought astronomical instruments to India. In 1792, they established their first observatory in Madras. The transit instrument of the Madras observatory was mounted on big granite pillars on which an inscription in Latin, Tamil, Telugu and Hindustani announced : "Posterity may be informed a thousand years hence of the period when the mathematical sciences were first planted by British liberality in India." The remains of these pillars are still extant in Madras (Chennai).
The Madras observatory functioned for more than 100 years and carried out important astronomical obervations. The Indian astronomer Chintamani Raghunathachari, who was head-assistant at the Madras observatory, discovered a new variable star R. Reticuli in the southern sky in 1867. Also, it was from here, after 18 years of work, Thomas Glanville Taylor produced the Madras General Catalogue of 11015 southern stars, which was highly admired in Europe.
The British were more interested in the study of the Sun. Realising the benefit of India's sunny climate, observatories came to be established in Dehradun, Calcutta and Pune. But all of them were shut down much before India attained independence.
The Kodaikanal observatory was established in 1899 for studying physics of the Sun. John Evershed, who joined the observatory in 1907, personally built up several new instruments for solar investigations. Using one such instrument, in 1909 he made the important discovery : huge vortical motions of gases in sunspots (the Evershed Effect). After Evershed's retirement in 1923, the observatory continued to take solar pictures. It has a collection of solar photographs that now covers eight solar cycles.
After independence several new instruments were added to the Kodaikanal observatory. In 1958, a new solar telescope was purchased from the famous telescope makers of England, Grubb Parson & Co. Also, a Lyot filter for studying the chromospheric layers of the Sun was imported from France. In the International Geophysical Year (1957-58) the task of observing solar effects between Manila and Rome was given to the Kodaikanal observatory. That time Dr. A.K. Das was the director of the observatory. A crater on the invisible side of the moon is named after Dr. Das.
In 1909, a private observatory, later named as Nizamia (Nizam's) Observatory, was set up at Hyderabad. Its founder was Nawab Zafar Jung, an England-educated rich noble man. Taken over by the government in 1907, the observatory for years worked on an ambitious programme of photographing and charting a large segment of the sky. After independence the observatory received special grants for its modernization. When the 40 inch (1.2 metre) reflector arrived in 1968, it was erected at a new site named Japal-Rangapur after the two neighbouring villages not far from Hyderabad. In 1983 the Nizamia Observatory was also shifted from its old Begumpet site to a new building in the Osmania University campus. Now both the observatories, Nizamia and Japal-Rangapur, function under the Department of Astronomy, Osmania University.
In the first half of the 19th century a few other private observatories were also established in India. The Nawab of Oudh, Nasiruddin Hyder, established an observatory in Lucknow in 1832 and equipped it with some fine instruments. But it was soon closed down and was ransacked in 1857 at the time of the Mutiny. Another observatory was set up at Trivandrum in 1836 by the Raja of Travancore, Rama Vurmah, who desired "that his country should partake with European nations with scientific investigation". It also met the same fate as the observatory at Lucknow.
Thus, at the time of independence there were only two observatories functioning in India : one at Kodaikanal and the other at Hydrabad. At that time Shapley was quite right when he said that India's observing facilities were practically nil. But he had also said that India produced great astronomers like Meghnad Saha and Subrahmanyan Chandrasekhar. Saha in 1920 produced his famous Ionization equations, which were of great help in understanding stellar atmospheres. S. Chandrasekhar applied the theory of special relativity to problems of stellar structures in the 1930s and obtained results which later came to be known as 'Chandrasekhar limit' for which he received the belated Nobel Prize in physics in 1983.
A few years before independence efforts were made to establish some new scientific institutions in the country. To estimate the requirements of astronomical research, a committee was formed in 1945 with Prof. Meghnad Saha as its chairman. The recommendations of the committee included several suggestions for improvement in the existing observational facilities. It also strongly recommended that efforts should be made to establish a fairly large observatory where Indian scientists could do astronomical research independently. But because of the political changes that followed and Saha's sudden death in 1956, it took a long time to implement the recommendations. The credit for making Saha's dream a reality goes to Dr. Manali Kallat Vainu Bappu.
In 1948, the American astronomer Harlow Shapley was in India. That very year Vainu Bappu had obtained his master's degree in physics. His father being an astronomer in Nizamia observatory, Vainu Bappu had developed a great interest in astronomy. He wanted to follow a career in astronomy and was in search of an opportunity. The opportunity came when Harlow Shapley was in Hyderabad, and Vainu Bappu met him in his hotel. The result was that Vainu Bappu found himself in Harvard in early 1949 on a Government of Hyderabad scholarship to do research in astronomy.
At Harvard, Bappu got the opportunity to work with new instruments and better facilities. Within a few months, after his arrival at Harvard, Bappu and his two colleagues discovered a new comet, which was named as 'Bappu-Bok-Newkirk Comet'. In 1952, Bappu got the opportunity to work with the Palomar 200-inch telescope, the largest in the world at that time. During that period Bappu and Prof. Olin Wilson jointly discovered what came to be called "Wilson-Bappu Effect". This is one of the fundamental relations often used in determining a star's luminosity.
Bappu returned to India in early 1953 and got an offer to build an observatory in Uttar Pradesh. With the help of Dr. Sampurnanand, then Chief Minister of UP, Bappu established a new observatory at Manora Park in Nainital. He installed modern instruments in this new observatory and developed there a team of young astronomers under his guidance. In April 1960 Bappu left Nainital and came to Kodaikanal to take charge of the Observatory, then biggest in the country.
The most important recommendation of the Saha Committee was to establish in the country a big observatory which could match any other in the world. Bappu diverted all his vigour and attention to achieve this objective. His first decision was to locate the new observatory somewhere in south India. From such a location the southern sky would be within the reach of the observatory's instruments. In southern India Bappu searched several hills for a suitable location. At last, he selected the sandal-wood forested Javadi hills (North Arcot district, Tamil Nadu) for the site of his dream-observatory. The observatory was named after a small village nearby -- Kavalur. At Kavalur the first observations with an indigenously built 38 cm telescope were made in late 1967.
In Kavalur the one-metre Zeiss telescope was installed in 1972, and the very next month, during an occultation event, scientists discovered a trace of atmosphere on Gynymede, the largest satellite of Jupiter. Five years later the same telescope discovered the rings of Uranus.
Vainu Bappu also planned and worked hard for the erection of an indigenously built 93-inch (2.3 metre) telescope at Kavalur. But he did not live to see the realisation of his dream. This telescope, the largest in Asia, was set up in a big dome at Kavalur in 1985. In 1986, the Kavalur Observatory and the 2.3 metre telescope, both were named after the founder, Vainu Bappu. The International Astronomical Union, during its Assembly in India in 1985, unanimously decided to name a newly discovered asteroid as Vainu Bappu.
The first observatory after independence was set up in 1954 at Varanasi and this was shifted to Nainital in 1961. In 1972 it acquired a 1-metre reflector, which later was named as the Sampurnanand Telescope. The Gurushikhar Infrared Observatory, Mount Abu, houses a 1.2 metre reflector along with stellar and infrared photometers. The Udaipur Solar Observatory was set up in 1975 on a small island in the Fatehsagar lake in Udaipur. It has three telescopes for solar studies : helioseismology and chromospheric observations. Both the Mount Abu and Udaipur observatories are attached to the Physical Research Laboratory, Ahmedabad.
Before independence there was not a single radio telescopes in India. Now radio astronomical facilities exist at Ooty, Bangalore, Gaurubidanur, Ahmedabad and at Khodad near Pune. India's first major radio astronomical facility, the Ooty Radio Telescope, was set up in 1970 at Udhagamandalam in the Nilgiri Hills. It consists of 24 parabolic cylinders 530 metres long and 30 metres wide. The telescope has been used for studying distant radio sources, pulsars and supernova remnants. In the early eighties, at a distance of 4 kms, one more radio telescope was set up at Ooty.
The Giant Metre-wave Radio Telescope (GMRT) erected near Khodad, about 80 km north of Pune, has become operational in 1995. It is the world's largest aperture synthesis radio telescope at metre wavelengths. It consists of 30 fully steerable parabolic dishes of 45 metre diameter each. The main objective of this radio telescope is to search for the highly red-shifted lines of neutral hydrogen emanating from proto-galaxies and proto-clusters, with the aim of determining their time of formation.
Cosmic gamma rays are the most powerful electromagnetic radiation produced by nature. As these rays cannot reach the surface of the earth, they are studied by detectors aboard satellites. But they can also be detected on ground as high energy gamma ray photons, which are a component of the secondary cosmic rays. For Gamma-ray astronomy there are two facilities in our country : The High Altitude Research Laboratory at Gulmarg under Bhabha Atomic Research Centre (BARC) and the High Energy Gamma-Ray Observatory at Pachmarhi under Tata Institute of Fundamental Research (TIFR).
India has done very well in cosmic ray studies. Dr. Homi Bhabha (1909-1966) was a pioneer in this field. In the last few years, work has also been done in the area of X-ray astronomy, infrared astronomy and atmospheric science. There are facilities for astronomical and astrophysical studies in about a dozen Indian universities. To help the universities, the Inter-University Centre for Astronomy and Astrophysics was established at Pune in 1988. The first planetarium was set up in 1954 at New English School, Pune. Now there are about 30 planetariums in the country.
It was at the time of Sawai Jaya Singh that India came in contact with modern European astronomy. As noted by Harlow Shapley, in 1947 India had no facilities for astronomical observations worth the name. But now we have several first class facilities. The Vainu Bappu Observatory at Kavalur is one of the best in the eastern hemisphere. Also, the metre-wave radio telescope near Pune is among the most powerful in the world. Now, our astronomers' contribution is also receiving international recognition.
- Gunakar Muley
Illustrations : Captions
1. Sawai Jaya Singh II (1686-1743)
2. Delhi Observatory (Jantar Mantar)
3. Madras Observatory (1792)
4. Manali Kallat Vainu Bappu (1927-1982)
5. The Kavalur dome where the 2.3 metre Vainu Bappu telescope is installed.
6. The 2.3 metre telescope at the Vainu Bappu Observatory, Kavalur
7. Giant Metre-wave Radio Telescope at Khodad near Pune
8. Udaipur Solar Observatory
8. Udaipur Solar Observatory