UBV observations of the flickering of T CrB
ATel#8675               February 11, 2016

R. Zamanov, E. Semkov, K. Stoyanov (Institute of Astronomy and NAO, Bulgaria) & T. Tomov
(Nicolaus Copernicus University, Torun, Poland )

In 2015 the recurrent nova T Coronae Borealis has entered a super-active state (Munari, Dallaporta & Cherini, 2016, NewA, in press).
On February 7, 2016, we observed the flickering of T CrB in three filters (UBV) using the 50/70 cm Schmidt telescope of the National Astronomical Observatory Rozhen (Bulgaria). The total amplitude detected was about 0.16 mag in U, 0.08 in B, and 0.04 in V band. In the table are given as follows: the band, UT-start and UT-end of the run, exposure time, number of CCD images obtained, minimum, maximum and average magnitudes in each band, standard deviation of the mean, typical observational error.  The data can be downloaded from http://www.astro.bas.bg/~rz/TCrB/

A comparison with our previous observations shows that  the brightness increased with 1.5 mag in U. Surprisingly, the flickering amplitude decreased by a factor of 2 in U and B bands. In 2009 the flickering amplitude in U was not less than 0.30 mag, while now is less than 0.10 mag.
Our observations confirm the increase of the brightness in U and B bands and that T CrB is in active state. 
We encourage further multiwavelength observations.