A `CLEAN'-type Deconvolution Algorithm

Summary. The CLEAN deconvolution procedure is tested to find out (a) whether it can be used to improve resolution in the presence of low level Poissonian noise and (b) how well it actually removes "dirty" side lobes. It is found that a modification is necessary in order to make CLEAN more efficient in both resolution improving and side lobes suppression namely, the cleaning beam should be made sharper than the instrumental beam. A few test cases are presented and the CLEAN and modified CLEAN results are compared. A comparison is made with a maximum entropy algorithm for a simple case to which noise of amplitude of 20 % is added. Key words: the "CLEAN" technique numerical methods for beam changing