Circular and luminous UFO snapped over Hunstville

On September 24, 2014, a daughter has photographed, since Paddock Club Apartment Complex (located in Huntsville, Alabama), a perfect spherical-shaped UFO. What is it?

Witness reports:

My daughter was getting out of her car getting a photo of the sky (pretty clouds) and noticed this object in the photos days later. Have researched as much as possible and cannot find anything on the web that resembles this.