I would like to thank Prof. Klaus Jockers, Max-Planck-Institut für Aeronomie, Germany, for kindly providing the focal reducer, interference filters and CCD-camera for use at the 2m telescope of BNAO, and for numerous fruitful discussions about the effective use of this instrumentation. This collaboration was partially supported by the Deutsche Forschungsgemeinschaft, Aktenzeichen 436 BUL 113/61. I am grateful to Tanyu Bonev, Institute of Astronomy, Bulgarian Academy of Sciences and to Valeri Golev, St.Kliment Okhridski University of Sofia who provided helpful discussions. I would like to thank Zlatan Tsvetanov, Johns Hopkins University, who provided helpful discussions and comments. The images were partly processed on a DECpc 450 D2LP, granted by the European Southern Observatory in the framework of its Central & Eastern Europe Programme, project number A-03-031. Our research was supported by the Bulgarian National Scientific Foundation grant under contracts No. F-482/1995 and No. F-484/1995 with the Bulgarian Ministry of Education and Sciences. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
© European Southern Observatory (ESO) 1999
Online publication: March 10, 1999