A new study of the long-term and orbital variations of the Be star V923 Aql

The first part of this thesis deal with the topic of Be stars, their variability on different time scales and some of the models explaining formation of the envelope. Next part deals with software, which is used for measurement. After introduction to these programs the data analysis follows. Overall, 46 spectra from Ondřejov Observatory and Hvar photometric observations that covered time RJD=52000- 58500 has been used. Each finding were compared with already known properties of V923Aql. Most behavior patterns that were seen in the past has been seen even in the available data, but a difference between RVHα and RVM measured on metallic lines were found. Also, the length of long-term cycle seems to differ from that in the past cycles.