IUCAA, NCRA and IIA: What India's Top Astronomy Institutes Do Every Day

On any given morning, a postdoctoral researcher at the Inter-University Centre for Astronomy and Astrophysics in Pune might be running a simulation of how dark matter clumps around galaxy filaments, while sixty kilometres away at the National Centre for Radio Astrophysics, an engineer is checking the health of 30 dish antennas spread across the Pune countryside, and in Bengaluru, an observer at the Indian Institute of Astrophysics is queuing up a night's worth of targets for the Himalayan Chandra Telescope, operated remotely from Leh. These are not occasional activities. They are the daily rhythm of Indian professional astronomy.

IUCAA was established in 1988 with a mandate that is unusual for a research institute: it exists not only to do research but to build the capacity for research across every Indian university. Its permanent faculty work on gravitational wave physics, large-scale structure, cosmology, and high-energy astrophysics, but a significant fraction of the institute's daily effort goes into hosting visiting scientists from universities that have no telescope access, no supercomputing time, and no critical mass of colleagues to argue with. The IUCAA library and its computing cluster are, for many Indian university astronomers, the only serious infrastructure they ever touch.

The institute's gravitational wave group became internationally prominent after LIGO's first detection in 2015. IUCAA is a full institutional member of the LIGO Scientific Collaboration, and its researchers contribute to the data analysis pipelines that sift detector noise for the signature of colliding black holes and neutron stars. When the LIGO-India detector is eventually built at Aundha Nagnath in Maharashtra, IUCAA will be one of its primary scientific homes. Day to day, this means software development, pipeline testing, and analysis of archival LIGO data, work that looks more like applied mathematics than stargazing.

The National Centre for Radio Astrophysics operates the Giant Metrewave Radio Telescope, or GMRT, located about 80 kilometres north of Pune near the village of Khodad. The GMRT is an array of 30 fully steerable parabolic dishes, each 45 metres across, spread over a roughly 25-kilometre baseline. At the metre wavelengths it was designed for, it remains one of the most sensitive radio telescopes in the world. A major upgrade completed around 2019, called the upgraded GMRT or uGMRT, extended its frequency range and improved its sensitivity significantly.

On a typical observing day, the GMRT runs back-to-back proposals from researchers across India and from international teams who apply through open time calls. The telescope has been used to detect the most distant neutral hydrogen ever observed, to study pulsars with extraordinary timing precision, to map the diffuse radio emission around galaxy clusters, and to hunt for the signatures of the epoch of reionisation, the period when the first stars lit up the early universe. The engineering team at NCRA maintains the receiver systems, the correlator that combines signals from all 30 dishes, and the fibre links that carry data from the field antennas to the central building. This maintenance is not background work. A radio telescope at metre wavelengths is fighting radio frequency interference from mobile networks, aircraft, and satellites every hour it operates.

The Indian Institute of Astrophysics, headquartered in Koramangala in Bengaluru, operates telescopes at three distinct locations: Kavalur in Tamil Nadu, Hanle in Ladakh, and Gauribidanur north of Bengaluru. The Vainu Bappu Telescope at Kavalur, with its 2.3-metre mirror, is one of the largest optical telescopes in Asia. The Indian Astronomical Observatory at Hanle, at an altitude of about 4,500 metres, hosts the Himalayan Chandra Telescope and the GROWTH-India telescope, and its extreme altitude and dry, dark skies make it one of the best optical sites in the country.

IIA's research spans stellar physics, solar astronomy, interstellar medium studies, and instrumentation development. The solar group operates the Kodaikanal Solar Observatory, which holds a photographic archive of the Sun going back over a century, one of the longest continuous solar records anywhere. Researchers there study sunspot cycles, solar flares, and the connection between solar activity and Earth's upper atmosphere. The instrumentation group builds spectrographs and cameras that go onto Indian telescopes and, through collaborations, onto international ones. Building an instrument from scratch, designing the optics, machining the mechanical parts, writing the control software, testing it in the lab, and then commissioning it on a telescope, can take several years and involves physicists, engineers, and technicians working in the same building on the same object.

All three institutes feed students into the same national PhD ecosystem. IUCAA, NCRA, and IIA each admit graduate students through the Joint Entrance Screening Test for astronomy and astrophysics, known as JEST, and through the CSIR-UGC NET. A student who joins any one of them will spend time at the others through workshops, collaborative projects, and the national astronomy meeting held under the Astronomical Society of India. The institutes also share telescope time in practice, with IIA observers sometimes using GMRT data and NCRA theorists collaborating with IUCAA's cosmology group.

India's astronomy infrastructure is growing outward from these three centres. The proposed National Large Optical Telescope, a 10-metre class instrument, is being designed with IIA as a lead institution. The LIGO-India project anchors IUCAA and NCRA in the global gravitational wave network. The Square Kilometre Array, the next generation of radio telescope being built in South Africa and Australia, has NCRA as India's nodal centre. The daily work at all three institutes, the simulations, the antenna checks, the queued observations, is also preparation for instruments that do not yet exist.