1 Introduction

The Coma-A 1367 supercluster is part of the Great Wall, the major large-scale structure in the Northern Hemisphere (Zabludoff et al. 1993). This supercluster provides us with a unique test-bed for extragalactic investigations since it contains thousands relatively bright galaxies ($m_{\rm p}< 15.7$) at high galactic latitude, thus little affected by extinction from our Galaxy, distributed in a variety of environments spanning from rich clusters (Coma + A 1367) to relatively low-density regions. Furthermore, due to its narrow distribution in the redshift space relative to its average recessional velocity (7000 $\rm km\,s^{-1}$), the distance spread of its members is minimal. These properties make the Coma supercluster ideal for studying the environmental dependence of the properties of galaxies (e.g. their luminosity function) spanning a local density regime of over an order of magnitude. This structure has been studied in increasing details in the last decades, as new redshift measurements became available. The pioneering work of Gregory & Thompson (1978) unveiled the main structure of the supercluster within the region $11^{\rm h}30^{\rm m}<\alpha<13^{\rm h}30^{\rm m}; 18^{\circ}<\delta<32^{\circ}$. By that time only 238 of the 1130 galaxies brighter than 15.7 catalogued in the CGCG (Zwicky et al. 1961-68) in this region, had known redshift values. Ten years later the analysis of Gavazzi (1987) counted more than twice as many velocity measurements (695) obtained from optical (de Lapparent et al. 1986; Huchra et al. 1990) and 21 cm spectra (Giovanelli & Haynes 1985). The recent determination of the luminosity function of galaxies in this region by Gavazzi et al. (1995) relied on 941 redshifts. However complete optical and near-IR photometry was available for the late-type population only (Gavazzi & Boselli 1996). Since then the photometric survey was extended to cover the early-type galaxies as well, at least in the near-IR (Gavazzi et al. in preparation), while measurements in the visible are still under way. The full exploitation of this photometric material requires extending the redshift survey to the remaining 189 unmeasured galaxies. For this purpose we undertook the spectroscopic survey presented in this paper. The sample is presented in Sect. 2, the observations and data reduction in Sect. 3. The new redshift are given in Sect. 4 and are used, joint with the measurements from the literature, to study the 3-D structure of the Coma supercluster.