APS Catalog of Galaxies behind Virgo

In addition to the different scanning mode, we have employed a different star-galaxy separation method and have visually inspected POSS prints to verify that each image remaining in the catalog is non-stellar.

The scanned fields are distributed generally in two areas, one around the outskirts of the Virgo Cluster, the other toward the antipode of the cluster (but still in the northern celestial hemisphere). The catalog gives the position of the center of each galaxy; estimates of the blue and red magnitudes within the outermost threshold crossing and of the blue magnitude extrapolated to zero surface brightness; blue and red diameters of four ellipses fit to the four threshold crossings (approximately 23.8, 23.6, 23.2, and 22.7 mag per square arcsec in blue, and 22.5, 22.4, 21.5 and 21.2 mag per square arcsec in red), and the ellipticities of those four ellipses.