At the end of season two of The Gilded Age, a battle between two opera houses — the Metropolitan Opera and the Academy of Music — comes to a head, with Bertha (Carrie Coon) emerging victorious at last, gazing out over the star-studded premiere she facilitated. In order to re-create the opening of the Met and capture Bertha’s triumph, cinematographer Manuel Billeter used visual effects and on-location shooting at the Academy of Music in Philadelphia. “This opera house, as we see it, doesn’t really exist,” explains Billeter. The front of the house, with the columns, was captured in Philly: “Bob Shaw, our production designer, felt it had the scope and the majesty to really convey this enterprise,” he elaborates. But the Academy of Music does not have boxes, key to…