Before any spectacle begins on stage, the audience inside the Metropolitan Opera House are treated to the sight of the chandeliers rising dramatically up to the ceiling. It’s an experience cited by some as reason enough alone to attend a performance at the Met. A gift from the Austrian government, the “sputnik” space-age crystal chandeliers are going through their annual summer cleaning, and the 11 that light the lobby are headed back to their Viennese birthplace for refurbishing. Swarovski is sponsoring the effort and donating new crystal. They will be back in time for the start of the Met’s 125th-anniversary season in the fall. More of the lights will be re-worked next summer.