1 Introduction

In the era of digitized sky surveys and of various methods to automatically tell galaxies from stars, a visual examination of photographic plates or film copies might easily be considered to be obsolete. However, at low galactic latitudes it becomes quite difficult to distinguish the often very dim and small galaxies from stars and other diffuse objects. This implies that an automatic detection of galaxies is severely hampered since one would be forced to check most candidates visually. As a consequence, visual surveys should be given preference - provided they are carried out by persons with appropriate experience of this type of work.

We have demonstrated that useful information can be obtained by visually inspecting photographic prints; particularly, we could gain experience during optical searches for galaxies in the "zone of avoidance'' (ZOA) of our Galaxy (e.g. Weinberger 1980; Weinberger 1995; Seeberger et al. 1996; Saurer et al. 1997). Extragalactic research in the ZOA is, for almost one decade, a quite booming area. A flourishing identification industry has led to the discovery of many thousand mainly optically identified extragalactic objects in a zone that was, by Hubble (1934, found to be practically devoid of galaxies. This development was and is, from a purely scientific point of view, triggered by several developments. One is the discovery of large-scale structures in the Universe and the insight that these structures will, of course, not come to a halt when approaching the ZOA. A second are the discussions about the Great Attractor that was suspected to be located at low galactic latitudes. Third, scientists also take the pick out of the bunch by the discovery and investigation of highly obscured (massive) nearby galaxies (e.g. Kraan-Korteweg et al. 1994; Huchtmeier et al. 1995).

Due to the favorable plate material (fine grain emulsions and considerable deepness), optical surveys for galaxies were particularly promising for the southern hemisphere. Major surveys there are those performed by Kraan-Korteweg (1996) and Saito et al. (1990), Saito et al. (1991) and Yamada et al. (1993).

In the northern hemisphere, due to the fact that only a small fraction of the new deep POSSII atlas was available up to the mid-nineties, the POSSI-E (red-sensitive) prints - less deep and having worse resolution compared to the southern plates or films - were used for analogous searches. Now, almost all of the POSS II film copies are available, and visual inspections on this excellent material should consequently result in the detection of many more galaxies. This prompted us to examine a promising part of the northern ZOA for non-stellar objects, the results of which are presented in this paper.