GMRT observations of interstellar clouds in the 21 cm line of atomic hydrogen

Nearby interstellar clouds with high (\v\ greater than or equal to 10km s(- 1)) random velocities although easily detected in NaI and CaII lines have h itherto not been detected tin emission or absorption) in,the HI 21 cm line. We describe here deep Giant Metrewave Radio Telescope (GMRT) KI absorption observations toward radio sources with small angular separation from brigh t O and B stars whose spectra reveal the presence of intervening high rando m velocity CaII absorbing clouds. In 5 out of the lei directions searched w e detect NI 21cm adsorption features from these clouds. The mean optical de pth of these detections is similar to 0.09 and FWHM is similar to 10 km s(- 1), consistent with absorption arising from CNM clouds.