Professor Rajesh Kumar Kochhar passed away in Chandigarh on 13 March 2022, aged 75 years. An ‘astrophysicist turned historian of science’ as he described himself, Kochhar has published well-researched books: Astronomy in India (jointly with J.V. Narlikar, INSA, 1993, 1995), The Vedic People (Orient BlackSwan, 2000), English Education in India, 1715-1835 (Routledge, 2021) and Sanskrit and British Empire (Routledge, 2022).

Rajesh Kochhar, son of a highly principled doctor from Chandigarh who worked to heal his patients, obtained his Ph.D. from the Panjab University, Chandigarh in 1973 working with Prof. S.K. Trehan in the area of stability of rotating masses with magnetic fields. After a brief stint as a lecturer at Panjab University, Kochhar joined the Indian Institute of Astrophysics (IIA) in 1974 and worked there till 1999. IIA was provided laboratory space in the Raman Research Institute (RRI) when he joined, and moved to the Koramangala campus after the completion of its first building in 1975. Kochhar’s logical thinking, clarity of expression, inclusive ideology, wit, and down to earth attitude won him many friends at RRI, IIA and among intelligentsia around Bangalore, and he continued to gather friends and admirers throughout his life. At IIA, he diversified his research into areas of supernovae, their remnants including pulsars, and dynamics of stellar systems. In a work with his student, Som Sunder, they were sharp eyed enough to spot and point out a rare error by S. Chandrasekhar in an application of the tensor virial theorem to galaxy dynamics. Kochhar spent a year at the University of Götingen Sternwarte as a DAAS Fellow in 1978-79.

A few years later, Kochhar turned his attention towards the historical heritage of Indian Institute of Astrophysics, history of astronomy in the Indian subcontinent during the colonial period and beyond, and history of people who composed the Rigvedic hymns. He received the British Council/Charles Wallace Trust Fellowship in 1991 that provided him access to historical documents in London. He won the Jawaharlal Nehru Fellowship (1996-97) for a project on Modern science in India: A historical study in the national and global context. During this fellowship he spent a few months at the Department of History and Philosophy of science at Cambridge University as a visiting scholar and a few months at Chicago Academy of Sciences as a Fullbright Lecturer on Imperialist use of science and the native response: The Indian experience.
Kochhar moved to the National Institute of Science, Technology and Development Studies (NISTADS, CSIR), New Delhi as its Director (1999-2006), and later to National Institute of Pharmaceutical Education and Research (NIPER), Mohali as a Professor of Pharmaceutical Heritage (2006-08). Thereafter he was associated with Panjab University as well as Indian Institute of Science Education and Research (IISER), Mohali as an Honorary Professor. He continued to write on history and sociology of science and technology, biography of eminent scholars, and any matter that he considered important or interesting enough to express his balanced views upon. He was active till the very end with his last book published in September 2021 and an article in print media on 31 January 2022. He was active on social media often posting one-liner criticism that was either direct, or veiled in humour.

Kochhar’s work on the history of science has won him Prof. R.C. Gupta Endowment History of Science Lecture Award (2006) of National Academy of Sciences India, Indira Gandhi Prize for Science Popularization (2014) of Indian National Science Academy. He served as the President of International Astronomical Union Commission 41 on History of Astronomy 2012-15 and was also a member of the Organizing Committee of Commission 46 on Astronomy Education and Development during the same triennium. He was also member, Editorial Board of Journal of Astronomical History and Heritage, New Zealand since it was founded in 1998 and served till 2015.

Kochhar’s body of work on history and sociology of science and technology overshadows his early work on theoretical astrophysics. Though he often depended on secondary sources available in English or other modern languages unlike hard-core historians who learn ancient languages and research on original sources, Kochhar applied scientific methodology and rigorous logic to the material he gathered to construct a historical narrative that was comprehensible to both scholarly historians and interested laypersons. His narratives are not biased by any ideological perception and bear evidence to his intellectual honesty. He was aware that “history cannot provide proof; it can only provide illustration. This, however, does not mean that history is a free-for-all, and can never be definitive. Uncertainty in history lies at the level of the significance of events, not at the level of events themselves” (The Vedic People). The events provided evidence to him, and the rest was a logical analysis leading to a coherent conclusion that could evolve with further evidence.

Kochhar viewed the development of science and society as a multicultural, multi-ethnic endeavour, whether in the Indian subcontinent or in the global arena. While he was open to re-interpreting history without distorting evidence, he was a staunch and open critic of modification of evidence to reach a politically rewarding narrative. While he placed his views vehemently, he was open to criticism and arguments against his views. An extrovert, he tested his ideas in open debate with people around him, and found working from home without face-to-face interaction during the pandemic very stressful. He looked towards a future where the heritage of all people was respected equally within India as a nation, and at the future global civilization. He had a habit of providing advice whether sought or not, generally towards progress in career or in personal life, and the peers who resisted them often found he was right and followed the advice quietly. Many younger persons, particularly students, accepted him as a mentor and did well. Though he occasionally lost temper during arguments with colleagues, he was generally gentle, especially with the younger people. He recalled that he was punished neither by elders at home nor by his teachers, and advocated that punishment stunts intellectual growth. He ended his last lecture at NIPMER with his characteristic optimism:
“25 years from now, India will be celebrating 100 years of its Independence. Most of our young friends who are sitting in the audience today will be speaking from various forums. I have no doubt that the stories you narrate will be of hope, optimism, achievements, and accomplishments.”

Kochhar was an active member of the Astronomical Society of India (ASI), served on committees and was Associate Editor of the Bulletin of ASI during the 1980s.
Kochhar married Dr Bimla Jhamb, who taught Physics for several years at colleges in Bangalore. Their daughter Garima grew up to study physics and computer science at the Birla Institute of Science and Technology, Pilani.
Rajesh Kochhar is survived by his spouse Bimla, daughter Garima and two grandchildren, brothers and a sister.

By Tushar Prabhu with inputs from Jagdev Singh, Ramesh Kapoor and Rajaram Nityananda