Indian Institute of Astrophysics

1. Indian Institute of Astrophysics a premier Institute for Research & Development in Astronomy & Astrophysics IIA- Gauribidanur Radio Observatory Radio astronomy facilities for observations of Sun started at Kodaikanal during 1950’s and 60’s with a 100MHz interferometer with Yagi type antennas and a 20-feet paraboloid for work at meter wavelengths range. Since 1976, the Institute operates a decametre wave radio telescope (GEETEE) jointly with the Raman Research Institute at Gauribidanur about 100 km north of Bangalore. The telescope consists of 1000 dipoles arranged in a 'T' configuration, with a 1.4 km East-West arm and a 0.5 km South arm. It has been engaged in the study of radio waves at 34.5 MHz emanating from Sun and other diverse objects in the sky. Gauribidanurradioheliograph (GRH) for obtaining two dimensional pictures of the outer solar corona simultaneously at different frequencies in the range 40-150 MHz was set up in 1997. A high resolution radio spectrograph is used in conjunction with GRH for obtaining dynamic magnetic field spectrum of transient burst emission from the solar corona. The antenna system consists of 8 log-periodic dipoles. A commercial spectrum analyzer is used as the back-end receiver to obtain spectral information with an instantaneous bandwidth of ~250 KHz. Based on theoretical formulations for the response of a correlation telescope to polarized radiation, an east-west one-dimensional array of 32 log-periodic dipoles have been set up to probe the coronal magnetic field at different heights above the solar surface. Arial View of E-W arm of GEETEE A section of the South arm of the GRH The polarization array