Unidentified

As I was processing this burst of shots I realised there was a moving object tracking across the upper left section as you look at it. A bird, a plane, a UFO?? Plainly a UFO; it's flying, it's an object and I can't identify it! The individual images show it more strongly, stacking the 7 frames has smoothed it out somewhat.
The sunspots are still harbouring a lot of unstable energy although they haven't released it yet.