The large, bright QSO survey. III - QSOs in six equatorial fields

This is the third paper in a series aimed at selecting ~1000 QSOs brighter than B_J_~18.7 using machine-scanned direct and objective-prism plates from the UK Schmidt Telescope. The plate material is scanned at the Automated Plate Measuring facility. The candidate list is derived using a number of complementary selection algorithms ranging from "traditional" criteria, such as the presence of strong emission features, to criteria designed to select objects whose objective-prism spectra cannot be classified as normal stars, although they may possess no obvious QSO-like features. Follow-up spectroscopy at the Multiple Mirror Telescope is used to classify each candidate. In this paper we present results from six new UK Schmidt Telescope equatorial fields in which 335 QSOs have been found in a total area of 190 square degrees, equivalent to an effective area of 169 square degrees once allowance for the fraction of unprocessed spectra is made. We also report the detection of a further 29 QSOs in the four fields in Virgo discussed in the first paper of this series. We present coordinates, magnitudes, redshifts, and spectra of moderate resolution and signal-to- noise ratio for all 365 QSOs as well as for nine additional extragalactic objects which fail to meet our absolute magnitude criterion as QSOs.