Instantaneous positions of microwave solar bursts: Properties and validityof the multiple beam observations

The multiple beam technique determine burst sources positions when their an gular extent are small compared with the beam shapes. We show for the first time that we carl check the above condition with the simultaneous observat ion using at least four beams. The developed technique is not critically de pendent on source shapes. By means of simulations me found that for narrow 1 arcmin long sources the uncertainties in position determination are less than 5 arcsec, and much better for symmetrical sources. The influence of si de lobes on source positions determinations was found to be negligible. A q ualitative method was developed when data from only three beams are availab le. Both methods are applied to the analysis of a solar burst observed with multiple beams at 48 GHz with the Itapetinga 13.7 m antenna. The multiple beam technique also offers the unique advantage to determine flux density i rrespectively from the position displacements of the source with respect to the beams, or vice versa.