Optical galaxies within 8000 kms -1- I. The density field.

The density field of optical galaxies to a depth of 8000 km s^-1^ over 67 per cent of the sky is determined using the UGC and ESO catalogues. The reconstruction method compensates for the varying completeness of the redshift data and for the galaxies that are not selected in the catalogues. The optical density field is dominated by supercluster complexes with dimensions in excess of 6000 km s^-1^. The most prominent of these are Perseus-Pisces and Centaurus-Hydra-Virgo-Pavo. The same complexes are seen in maps of IRAS galaxies, but the contrast of the optical maps is higher by a factor of 1.35+/-0.16 when measured in 2500 km s^-1^ cells. By comparing the overdensity of galaxies in the Virgo supercluster to Virgo infall and assuming that mass follows light, we obtain {OMEGA} = 0.20_-0.14_^+0.30^. The `Great Attractor Region' covered by Dressler's Supergalactic Plane Survey is overdense to 6000 km s^-1^, well beyond the Cen 30 cluster. However, unless there is a massive supercluster hidden in the zone of avoidance, this region is not sufficiently overdense for it to be identified with the Great Attractor inferred from D_n_ - σ and Tully-Fisher peculiar velocities. Furthermore, within the Centaurus-Hydra-Virgo-Pavo complex, the density field peaks close to the Cen 30 cluster, which suggests that large-scale streaming motions may be better described by a weak 200+/-150 km s^-1^ infall centred near Cen 30, plus a bulk dipole motion of 400+/-150 km s^- 1^ in the CMB frame.