The 2dF QSO Redshift Survey - III. The input catalogue

The 2dF QSO Redshift Survey (2QZ) has obtained redshifts for in excess of 23 000 QSOs selected by their u′, b J, r colours using the 2-degree Field (2dF) facility at the Anglo-Australian Telescope (AAT). In this paper, we describe the creation of the input catalogue from UK Schmidt photographic plates. All the plate materials used are described along with the techniques developed for flat-fielding variations in the photometric response of photographic emulsions. The selection criteria used for the survey are defined and their rationale discussed. Finally, several simple astrometric and photometric tests are performed. These demonstrate that, over the majority of the parameter space covered by this survey (18.2