Аннотация:MASTER OT J104031.63+061721.8 - flaring blazar at the historical highest level MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 10h 40m 31.63s +06d 17m 21.8s on 2013-03-31.59076 UT. The OT unfiltered magnitude is 15.7m (limit 18.6m). The OT is seen in 3 images. We have reference image without OT on 2010-03-17.64138 UT with unfiltered magnitude limit 18.0m. The object was previously detected at 16.3m on MASTER-Amur image of 2012-12-17.673 UT.