PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE 107, Page 99-102, https://doi.org/10.69646/14sbac16p
PPROCEEDINGS OF THE XIV SERBIAN-BULGARIAN ASTRONOMICAL CONFERENCE, Vrnjačka Banja, Serbia, September 23-27, 2024, Eds. Milan S. Dimitrijević, Evgeni Semkov, Zoran Simić, Goran Damljanović, Momchil Dechev
Published by: Astronomical Observatory, Volgina 7, 11060 Belgrade 38, Serbia

Blazars (subclass of active galactic nuclei) eject relativistic jets near the observer’s line of sight. Their flux is highly variable in the whole electromagnetic spectrum. Variability time-scales can be divided into three classes: intra-night variability, short-term variability, and long-term variability. The one subclass of blazars is BL Lac. These are blazars with rapid and large-amplitude flux variability. Source 1722+119 is BL Lacertae. The observations have been performed from July 2013 using telescopes located at the Astronomical station Vidojevica of Astronomical Observatory of Belgrade, Serbia. During more than ten years of flux monitoring of source 1722+119 amplitude brightness change by about 2 magnitudes in V and R bands. We monitored this source for about 3 hours per night on several nights to investigate the intra-night variability, and the results are presented here.