FIRST extra-galactic surveys: practical considerations

We discuss some of the practical considerations that need to be made in the design of extra-galactic field surveys using FIRST. We investigate the various limitations that confusion noise imposes on possible FIRST surveys and the benefits of super resolution or decconvolution techniques. We consider the possible sizes and depths of survey fields in order to meet many of the scientific objectives of the FIRST mission. In particular we discuss the factors that need to be taken into account in selecting the survey fields. The final choice of fields will be influenced by the location of other surveys that are currently being planned; so it is vital that the FIRST community begin debating this issue now. We conclude that a substantial survey of order of 100 square degrees is likely to be sited in the region of the SIRTF Legacy survey, SWIRE.