This target in the constellation of Cygnus, V404, is known to be a black hole binary paired with a near solar mass companion. On June 15, 2015 it went into outburst rising from magnitude 19 to about magnitude 12.
I first observed the target on June 19 and the outburst was continuing. Here is a light curve of it's activity.
This chart contains observations over about a four hour period. The dark dots show the changes in brightness over the period, the red dots show a nearby comparison star which as you can see, is unchanging. Each dark dot is a 30 second exposure, measured with photometric software. Since each dot is 30 seconds, changes in brightness at the two or three minute level can be seen. Very exiting.