  In this paper, we review the results of interplanetary scintillation (IPS)
observations made with the legacy system of the Ooty Radio Telescope (ORT) and
compare them with the possibilities opened by the upgraded ORT, the Ooty Wide
Field Array (OWFA). The stability and the sensitivity of the legacy system of
ORT allowed the regular monitoring of IPS on a grid of large number of radio
sources and the results of these studies have been useful to understand the
physical processes in the heliosphere and space weather events, such as coronal
mass ejections, interaction regions and their propagation effects. In the case
of OWFA, its wide bandwidth of 38 MHz, the large field of view of
$\sim$27$^\circ$ and increased sensitivity provide a unique capability for the
heliospheric science at 326.5 MHz. IPS observations with the OWFA would allow
one to monitor more than 5000 sources per day. This, in turn, will lead to much
improved studies of space weather events and solar wind plasma, overcoming the
limitations faced with the legacy system. We also highlight some of the
specific aspects of the OWFA, potentially relevant for the studies of coronal
plasma and its turbulence characteristics.
