Backstage Ballet By KEN COY BEFORE THE AUDIENCE in Hoch auditorium last Thursday attending a Concert Series presentation unfolded a beautiful panorama of ballet-precise, graceful, perfect. But backstage the scene changes: a male star rushes into the wings to blot the perspiration from his face with a paper towel; the wardrobe people make quick repairs; the practice goes on. The hopeful seconds copy each motion of the masters they're understudying, mindful that in some future stand of the Ballet Theatre they may have their chance. And when one ballet is finished a clamor rises on the stage. Prop men shift scenery, lights are switched, costumes hurriedly donned. The ballet as art requires dedication—and all-inclusive background planning.