Several stellar discoveries by the 40-inch telescope at the Vainu Bappu Observatory in Kavalur, Tamil Nadu, were highlighted during the celebration of 50 years of its operation on 15-16 december. The telescope set up by Professor Vainu Bappu has played a significant role in astronomy with significant discoveries such as the presence of rings around the planet Uranus, a new satellite of Uranus, the presence of an atmosphere around Ganymede which is a satellite of Jupiter.
Other important research carried out by this telescope includes the discovery and study of many ‘Be stars’, lithium depletion in giant stars, optical variability in blazars, dynamics of the famous supernova SN 1987A and so on. The telescope at the observatory under the Indian Institute of Astrophysics (IIA), an institute of the Department of Science and Technology (DST), continues to be relevant thanks to the backend instruments that engineers and astronomers have built over the past 50 years to keep the telescope competitive among its peers.
Starting with the Cassegrain photometer and Echelle spectrograph in 1976, the new grating spectrograph in 1978, the fast-cutting polarimeter in 1988 with its replacement in 2016, and the latest NIR photometer in 2021, the observatory is constantly upgrading its facilities. “This telescope is witnessing technological changes in astronomical observations, from photographic plates to modern CCDs,” said Professor Annapurni Subramaniam, Director of the IIA. “I am confident that the facility will continue to be productive and used by scientists for years to come,” she added
By the 1960s, it was clear that India needed a quality optical observatory for research in modern astronomy, and after an extensive search, Professor Vainu Bappu chose Kavalur as the site for such an observatory. The sky above Kavalur was excellent and its southern position allowed it to see most of the northern and southern sky. A few years after the start of operation of the observatory, Prof. Bappu Carl Zeiss of Jena (then East Germany) an order for a 40-inch telescope, which was subsequently installed in 1972.
The telescope, whose mirror is 40 inches (or 102 cm) in diameter, was installed in 1972 and soon after began producing important astronomical discoveries. More than a generation of astronomers have been trained on this telescope as well. The expertise gained by the engineers also enabled the IIA to build a fully original 90-inch (2.34 meter) telescope in the 1980s.
To celebrate the golden jubilee of this extraordinary telescope, the IIA organized a one-day gathering at its Bengaluru campus on December 15, followed by a function at Kavalur on December 16. Many of the IIA’s retired astronomers, engineers and telescope assistants were invited to the event and received congratulations from the IIA Director.
There was a series of talks about important scientific discoveries from the 40-inch as well as personal memories of the personnel of the time. The 7th issue of the astronomy magazine “DOOT”, published by the students of IIA, was also published during this event. A 40-inch telescope painting competition was organized for primary school students in villages around Kavalur. The winners were awarded on the 16th at the observatory during the ceremony.
