tom_boston1

It's an internal reflection.  Anti-reflection coatings are designed to reduce things like this but sometimes when the source of light is too bright you still "ghosts" of this nature.  This kind of thing is much more identifiable if you are shooting things with multiple bright spots, like a birthday cake, because the multiple reflections keep the same relative position towards each other.

It really would have been a splendid photograph if you could have caught the balloon occulting the sun.  The overall contrast of the scene would have been much higher and the balloon likely would have had a very nice 

What lens was this and what is that background?  It's a rather unique pattern.