Astronomer’s Telegram #4068
T. Konstantinova, D. Blinov (St. Petersburg Univ.)
on 25 Apr 2012; 13:02 UT
We report on the recent optical activity of the high-mass X-ray binary system SAX J2103.5+4545. The source was monitored by 70-cm AZT-8 (CrAO, Ukraine) and 0.4-m LX-200 (St.Petersburg, Russia) telescopes. In the night of 2012-04-22 the brightness of the optical counterpart reached R= 13.27+/-0.02, as compared to R= 13.48+/-0.02 in the night 2012-03-23 and R= 13.65+/-0.02 in the night 2011-11-20. Last year, since ~ 2011-03-29, the system was in optical quiescent state. The previous optical activity observed from July 2010 to March 2011 was followed by onset of X-ray activity of the source (ATel #2925 and ATel #2928). New spectral observations of the system are desirable for monitoring a recent disc formation around the Be star.