UFO Sighting in Zürich, Zürich on June 7th 2015 – UFO hovering near stadium with ACDC concert during major lightning storm

I was watching the light show at the end of the ACDC concert at Letzigrund Stadium from the 20th floor of our building. A major lightning storm started and I grabbed my phone to take pictures of the lights from the concert coinciding with the lightning. I took all the pictures rapidly in quick succession and did not even seen the object captured in the photos until looking at the photos on my phone the next day. In the photos you can see that the object appears first as a pin point of blue/turquoise light, then develops 2 more green lights and the 4-5 total light green lights plus the bright turquoise light in the middle with a disc-shaped outline. The object appears to move around and to disappear or reduce itself to only the turquoise point of light during the lightning strikes. All photos were captured within an approx. 2 minute period through an open window with no flash. I have about 30 photos total of the object and have submitted the best 10.