1 Introduction

In a debate on the fraction of Be stars in young open clusters it is often forgotten that, in fact, a relatively small number of clusters has been deeply searched for the presence of Be stars. The objective-prism spectroscopic surveys which led to the discovery of the most of known Be stars are magnitude-limited and ineffective in crowded regions. In consequence, our knowledge of Be star fraction in clusters is usually confined to the brightest, that is, the early B-type stars. It is therefore possible that clusters with large number of Be stars could still be discovered. The use of CCD detectors and the H$\alpha$ filters opens a convenient way to fill in this gap, allowing both the crowded-field photometry and the detection of H$\alpha$ emission even in late B-type stars. With a moderate-size telescope even Magallanic Clouds clusters are within reach (Grebel 1997; Keller et al. 1999).

Among the galactic open clusters there are three that are usually mentioned as those which contain large number of Be stars. These are $\chi$ Persei, NGC3766, and NGC663 (Mermilliod 1982; Slettebak 1985). Of these, NGC663 is the richest in Be stars since about 35% of its B stars show H$\alpha$ emission (Maeder et al. 1999). In the percentage of Be stars, NGC663 is surpassed only by such Magellanic Clouds clusters as NGC330 and NGC1818A (Keller et al. 1999).

In the present paper we report results of our CCD H$\alpha$ photometry of the highly reddened galactic cluster NGC7419. We find in the cluster a large number of previously unknown Be stars.