why does this happen?

[nyamy]

probably an ignorant question, but I'm not sure and asking is the only way to learn. so here's the shot:

and here's the question:

what are those bright spots on the gazebo roof and in the lower right quadrant? sun? how to prevent that?

 

[mjeffries]

I could be wrong here and I'm sure one of the more experienced guys will correct me if I am, but...

Those are sunspots, caused by rays of light entering the lens from the side. A lens bonnet will help with that.

 

[Sim]

Looks like lens flare to me... Here's some info: http://en.wikipedia.org/wiki/Lens_flare

 

[Battou]

Yes that is lens flare. the light is literally bouncing around in the lens housing and casting a reflection