THE DATA REDUCTION OF RADIO OBSERVATIONS WITH SUB-ARCSECOND RESOLUTION

An extragalaactic radio source -NGC 5929 is obeerved by MERLINand VLAat multiple frequencies. The radio images achieved a resolution of the sub-arcsecond.There are serious disturbanes of the phase in the visibility at 408 MHz, due to theatmospheric effects above the antenna of MERLIN In addition, MERLINconsists ofseven telescopes. The array missed some information in (u, v) plane and causeddifficulty for mapping. The self-calibration and clean techniques are used to improvethe dynamic range of the images. The Hubble space telescope made the photographsof NGC5929 by the Planetary camra. In order to compare the optical line emittinggas with the edo endning plasma The 1.6 GHz contour map is superimposed on the[OⅢ] image. The paper introduces the data reduction method for NGC5929.