Super Mario 64

Hello,
In Super Mario 64 how do I get the winged hat? :(
I played this game a long time ago and I remember a light should appear in the middle of the castle, I just don't remember how to make it happen.If anyone can help, it'll really help me.Thanks, Dor.

how many stars do you have??

never mind, problem solved :D
I remembered now that I need 10 stars :D