Nostalgia...Kavalur Observatory's History

By amar_universe; Published 07 Jul 2011

There is a lot we can find on the web about Kavalur Observatory; I would request you to read that up. But while I was scouring through some links on specific history of our astronomy, I was lucky to come across a biography on Prof. M.K.V.Bappu by the reknowned astro-physicist Prof. J.C.Bhattacharyya of IIA.

Let us leave our time and turn the pages to the days when Kavalur Observatory was being conceived. Let us imagine to walk with the pioneer of Indian astronomy himself, Prof. Bappu.

The following account is an Open Access file and it's my duty to give credit to the Online IIAP Repository and the authors.


From Kannyakumari to the seven hills of Tirupathi, Bappu searched every hill for a suitable location. At last, he came across the sandalwood forested Javadi hills and immediately recognised the suitability of the place for his dream-observatory.

They carried a portable telescope and stopped at several places for a night of two and monitored seeing qualities there, and ultimately zeroed down to a spot in the Javadi Hills. The nearest village, just a cluster of mud-built huts, was about a kilometer away, the site derived its name from this small village, Kavalur.

Bappu arrived at his choice, Kavalur, from several serendiptious observations. The site is in the form of a hill, surrounded by a ring of still higher hills, beyond a horse-shoe shaped deeply wooded valley. The orography favoured formation of trapped air surrounding the observatory site, and the deeply wooded valley providing little insolation heating of the lower layers produced a relatively stable atmosphere. Bappu's idea was supported by a local forest ranger, who reported regular formation of low ground fogs in the surrounding valley on winter mornings.

Such a condition is conducive to good seeing, which was confirmed from observations in later years. Several times in the nights, the seeing better than 1 arc-second was recorded by the observers here. The reknowned astro-physicist Bart J. Bok had described the seeing at Kavalur as "excellent".

He arranged for a long term lease of 40 acres of forest land and set up the first instruments for astronomical observations. Kavalur Observatory thus came into existence : the first observations with an indigenously built 38-cm (15-inch) telescope were made in late 1967, which is functional even today.

He had selected the Kavalur site as early as 1962 and formed clear plans for its development. The location of various instruments among the greenery was chalked out by him even before the acquirement of the site.

He knew the location of every large tree in the campus ; the great lover of Nature that he was, he would not dream of felling them. Instead, he had only the undergrowth cleared and planned a forest of flowering trees like Gulmohor, Jacaranda and Cassia ; the roads that connected the telescope sites were to belined with rows of Bougainvillaea and Poinsettia.

Small cottages would dot the landscape, bearing the names of astronomers like Tycho, Kepler, Galileo and Copernicus, or the celestial nymphs of Hindu mythology: Urvasi, Menaka, and Rohini. They would be spaced artistically between the snow-white telescope domes. All these were planned and various sketches drawn while he was waiting for the clearance of his project from the administration.

The land was qiven on lease to the Kodaikanal Observatory (then a part of the Indian Meteorological Department) in 1967, and Bappu persuaded authorities to place an order with Carl Zeiss of West Germany for a one-metre telescope to be used in the new observatory. Plans of the building and dome for the new telescope were with the Central Public Works Department and it was five years before they could be built.

Barely a fortnight had passed after the installation of the telescope by May of 1972, when a rare occultation event observed at Kavalur brought in the unexpected evidence of a trace of atmosphere in Jupiter's largest satellite Ganymede.

Five years later, on 10th May 1977, the same telescope discovered the rings of Uranus, a major step in the advancement of our knowledge about the solar system.

Now talking about the large 2.3-metre telescope. The location offered not a very high number of cloud-free nights; Bappu wanted to install the large telescope in a site which offered good 'seeing' conditions of the atmosphere, in the Southern part of India. Bappu had already started this search in 1973 itself. He along with a team of young assistants went north of Bangalore, scouring Chikamagalur, Belgaum, Panchghani, Mahabaleshwar, Aurangabad area, and finally to Pachmarhi, staying and observing seeing conditions at each place for a few nights. It was noticed that as one moves north, the improvement in number of clear hours was very gradual, with increasing loss of access to southern skies. He felt that the southern location was still preferable; he clearly indicated in his report that in future when the question of locating a still larger telescope is taken up, some of these sites might be seriously considered.

Besides Kavalur, Bappu had chosen two more alternative sites: one in the Baba Budan hills of Karnataka and the second in the Horsely Hills in Andhra Pradesh. Two teams were sent to these sites to conduct comparitive observations for one full season. In the quality of sky transparency and seeing, no significant difference was found between the three stations, considering the advantage of a well established infrastructure already existing at Kavalur and on basis of good seeing condition, this site was recommended for location of the large telescope.

For the preparation of the site for the new telescope, an additional 60-acre forest land adjacent to the existing observatory was acquired. In November 1976 the IIA Council thus approved that the 93-inch telescope be located at Kavalur.

The Vainu Bappu Telescope (VBT) is the largest optical telescope at present in Asia; in the Asia-pacific region, except for the Anglo-Australian Telescope at Siding Springs, Australia, and a bank of super large reflectors on Mauna Kea, Hawaii, no other observatory in this region has optical telescopes of this size.