Optical observations of five X-ray selected BL Lacertae objects

We present optical data obtained with the 1.05 m telescope of the Torino As tronomical Observatory for five X-ray selected BL Lacertae objects. The dat a are in the Johnson's B, V: and Cousins' R bands. As the observing periods include the pointings of the Satellite per Astronomia X "Beppo" (BeppoSAX) , our optical information will be comparable with the X-ray observations fo r a better understanding of the properties of these objects. The present da ta also provide optical information on sources that have been rarely observ ed in the optical hand. Variability on short time scales (a few days) was f ound only for 1ES 1959+650.