Clean

Introduction

This documents contains information on adjusting parameters when using clean to optimize the algorithm. This document assumes a familiarity with the OSPEX object, referred to below as obj. It is also a space to keep track of any issues with the use of the algorithm

Parameters

• obj -> set, clean_beam_width_factor = 2 ; an example of setting the parameter, the default is 1

The clean_beam_width_factor changes the weighting factor that is convolved with the point sources the clean algorithm identifies before the image is reconstructed. Changing the factor is the equivalent of changing the beam size.

• obj -> set, clean_niter = 500; the default number of iterations is 100

This changes the number of iterations that the clean algorithm uses. The default of iterations will usually be reached for most images before the algorithm reaches a stopping point due to the value of the change in chi^2. The speed of the algorithm means that the number of iterations can be increased without a large increase in processing time.