Around half a century ago the Radio Astronomy Group at TIFR, under the leadership of Prof. Govind Swarup, embarked on an ambitious project to build a radio telescope at Ooty. This 530-m-long and 30-m-wide cylindrical parabolic reflector had a unique design that allowed it to track a source in the sky with a single rotation of the telescope along the long axis of the cylinder. In these four decades, several very significant scientific discoveries were made in observational cosmology, pulsars, recombination lines and the interstellar medium as well as the inner heliosphere. The Ooty Radio Telescope (ORT) continues to be in regular operation and is currently being used for space weather studies as well as pulsar observations.
The ORT is currently undergoing a major upgrade to its receiver chain, which will result in a new system called the Ooty Wide Field Array (OWFA). The OWFA is designed to function as a 264-element interferometric array, and to provide a significantly larger instantaneous bandwidth as well as field-of-view compared to the legacy ORT receiver system. In addition to significantly enhancing the capabilities for heliospheric studies, this upgrade is also expected to open other avenues of research particularly in the newly emerging areas of 21-cm intensity mapping and studies of transient radio sources. Articles in a Special Section of the March 2017 issue of the Journal of Astrophysics and Astronomy (http://www.ias.ac.in/listing/articles/joaa/038/01) present the scientific motivation, design and expected capabilities of this upcoming instrument.